proposal program riset dan inovasi itb 2011

Transcription

PROPOSAL
PROGRAM RISET DAN INOVASI ITB 2011
Pengembangan metoda pemantauan aktivitas
gunungapi berdasarkan pada sifat listrik dan
magnetik
Development of method for monitoring
volcanic activity derived from electrical and
magnetic properties
Ketua Tim Peneliti:
Dr. Nurhasan, S.Si, M.Si
KK
: Fisika Sistem Kompleks
Fakultas/Sekolah : FMIPA
INSTITUT TEKNOLOGI BANDUNG
September, 2010
DAFTAR ISI
Halaman
IDENTITAS PROPOSAL ..................................................................................................3
1
RINGKASAN PROPOSAL ..........................................................................................4
2
PENDAHULUAN ......................................................................................................5
2.1
Latar belakang masalah ...................................................................................5
2.2
Tujuan riset....................................................................................................6
3
METODOLOGI...................................................................................................... 11
4
DAFTAR PUSTAKA ................................................................................................ 14
5
INDIKATOR KEBERHASILAN (TARGET CAPAIAN) ..................................................... 15
6
JADWAL PELAKSANAAN ........................................................................................ 16
7
PETA JALAN (ROAD MAP) RISET ............................................................................ 17
8
USULAN BIAYA RISET ........................................................................................... 18
8.1
Belanja pegawai............................................................................................ 18
8.2
Belanja barang ............................................................................................. 18
8.3
Belanja jasa.................................................................................................. 18
9
CV TIM PENELITI ................................................................................................. 20
10
LAMPIRAN BUKTI CAPAIAN OUTPUT TAHUN 2009-2010........................................... 29
3
LEMBAR IDENTITAS
1. Judul
: Pengembangan metoda pemantauan aktivitas gunungapi
berdasarkan pada sifat listrik dan magnetik
2. Tim Peneliti
2.1 Peneliti Utama
a. Nama Lengkap
b. Pangkat/Golongan/Jabatan
c. NIP
d. Fakultas/Sekolah
e. Kelompok Keilmuan
f. Telpon/Fax Kantor
g. Email
h. Alamat Rumah
i. Telpon Pribadi
: Dr. Nurhasan S.Si.,M.Si.
: Penata Muda Tk. I/IIIB/Asisten Ahli
: 132231594
: Fakultas Matematika dan Ilmu Pengetahuan Alam
: Fisika Sistem Kompleks
: 022-2500834 /
: nurhasan@fi.itb.ac.id
: Komplek Pasir Pogor Blok RC No.9 Bandung
: 081394276972
2.2 Anggota Tim Peneliti
No.
Nama dan Gelar Akademik
Bidang Keahlian
Unit Kerja
Jam/mg
Bulan
1.
Prof. Doddy Sutarno, M.Sc, Ph.D
Induksi ELektromagnetik
FMIPA ITB
5
10
2.
Dr.rer.nat. Sparisoma Viridi, S.Si
Pemodelan Numerik
FMIPA ITB
5
10
2.2 Asisten Peneliti/Mahasiswa
No.
Nama dan Gelar Akademik
Bidang Keahlian
Status
Jam/mg
Bulan
1.
Imran Hilman,S.Si, M.Si
Pemodelan Numerik
Mhs S3
10
10
2.
Harsya Bachtiar
Akusisi data
Mhs S1
10
10
3. Biaya yang diusulkan
4. Urutan Prioritas Skema
: Rp. 50.000.000,00
: 1. Riset Desentralisasi DP2M Dikti (STRANAS)
2. Riset dan Inovasi KK
3. Riset The Osaka Gas Foundation
5. Target output (keluaran) Riset
No.
:
Nama/Jenis Output
Jumlah
1.
Jurnal Nasional ber-referee/terakreditasi
2
2.
Prosiding Konferensi Internasional
1
6. Proposal ini belum pernah didanai oleh atau diusulkan ke sumber lain.
Mengetahui
Ketua Kelompok Keahlian
Bandung, 30 September 2010
Peneliti Utama
(Dr.rer.nat. Umar Fauzi )
NIP: 131844768
(Dr. Nurhasan S.Si.,M.Si.)
NIP: 132231594
Dekan Fakultas Matematika dan Ilmu Pengetahuan Alam
(Prof. Dr. Pudji Astuti Waluyo MS)
NIP: 131572750
4
1. RINGKASAN PROPOSAL
Indonesia sebagai salah satu negara kepulauan yang terletak pada batas
tumbukan lempeng lempeng dunia merupakan negara yang memiliki resiko
bencana alam tinggi terutama bencana alam gempa bumi dan letusan gunungapi.
Sebagian besar gunungapi di Indonesia masih aktif dan terletak di daerah
pemukiman yang sewaktu waktu dapat menimbulkan bencana bagi penduduk
disekitarnya jika terjadi peningkatan aktivitas gunungapi apalagi jika sampai terjadi
letusan. Berbagai usaha telah dan sedang diupayakan pemerintah dalam rangka
mitigasi bencana baik dalah hal pengembangan pemantauan aktivitas gunungapi
maupun dalam upaya meminimalisasi dampak kerugian yang ditimbulkan oleh
bencana alam gunungapi ini. Salah satu sistem pemantauan aktivitas gunungai
yang saat ini digunakan adalah data seismik yang didasarkan pada besar kecilnya
getaran yang ditimbulkan oleh aktivitas gunungapi. Dalam penelitian ini akan di
kembangkan suatu metoda alternatif dalam memantau aktivitas gunungapi
dengan menggunakan metoda
elektromagnetik dan magnetik. Dalam metoda
yang diusulkan ini, perubahan struktur bawah gunungapi akan dipantau
berdasarkan paramter fisis resistivitas sedangkan metoda magnetik digunakan
untuk memantau perubahan sifat magnetik yang berhubungan dengan perubahan
temperatur bawah permukaan, sehingga pemantauan gunungapi akan lebih
komprehenship dan terintegrasi, dengan demikian informasi yang diperoleh akan
lebih akurat.
Metoda elektromagnetik merupakan metoda geofisika yang sangat sensitif
terhadap perubahan konduktifitas dibawah permukaan bumi sebagai akibat
berubahnya temperatur. Dengan memantau perubahan keberadaan daerah
konduktif dan sifat magnetik akibat perubahan temperatur yang berhubungan
dengan aditivitas gunungapi, maka pemantauan aktivitas gunungapi dapat
diperoleh sehinga diharapkan informasi yang lebih detail, akurat dan komprehensif
bisa didapatkan yang pada akhirnya dampak negatif dari kegiatan gunungapi bisa
diantisipasi lebih dini.
5
2. PENDAHULUAN
2.1. Latar Belakang
Negara Indonesia selain merupakan negara kepulauan, juga merupakan
negara yang mempunyai banyak gunungapi aktif. Tidak kurang dari 129
gunungapi aktif atau 13%-17% dari jumlah gunungapi di dunia terdapat di
Indonesia. Oleh karena itu, informasi aktivitas gunungapi yang lebih akurat dan
komprehensif mutlak diperlukan. Monitoring gunung dapat dilakukan dengan
beberapa metoda yang sudah dan sedang dikembangkan diantaranya dengan
metoda seismik, metoda GPS (Hasanuddin et al., 2001). Sumber informasi
tentang aktivitas gunungapi yang paling diandalkan pada saat ini adalah data
seimik yang didasarkan pada besar kecilnya getaran yang terjadi. Peralatan
seismik ini dipasang di sekitar gunungapi untuk medapatkan data berupa
peningkatan atau penurunan getaran akibat aktivitas gunungapi. Data yang
diperoleh pada metoda ini berupa data secara real time yang direkam
berdasarkan phenomena yang terjadi dipermukaan pada saat itu tanpa melibatkan
secara langsung informasi dari struktur bawah permukaan tubuh gunungapi
secara keseluruhan.
Dalam penelitian ini, berbeda dengan metoda yang selama ini digunakan,
kami akan mengaplikasikan dan mengembangkan metoda elektromagnetik dan
magnetik untuk mendeteksi perubahan struktur bawah gunungapi berdasarkan
parameter
fisis
resistivitas
dan
sifat
magnetiknya.
Kelebihan
metoda
elektromagnetik dalam memetakan tubuh gunungapi dibandingkan dengan
metoda geofisika lainnya adalah sensitifitasnya yang sangat tinggi terhadap
kontras resistivitas atau konduktivitas bawah permukaan (Nurhasan, et al., 2006).
Interpretasi data akan dilakukan melalui pemodelan elektromagnetik tiga dimensi.
Sementara itu, sifat magnetik suat batuan sangat berhubungan erat dengan
aktivitas gunungapi karena adanya perubahan temperatur akibat menaiknya
panas kepermukaan. Dengan menggunakan kedua metoda ini diharapkan hasil
pemodelan akan lebih baik sehingga informasi yang didapat lebih akurat. Analisa
perubahan
daerah
konduktif,
sifat
magnetik
dan
hubungannya
dengan
sifat/parameter fisis yang lain (temperatur) akan memberikan informasi yang lebih
komprehensif dan terintegrasi tentang aktivitas gunungapi yang terjadi sehingga
6
informasi yang didapat bukan saja bermanfaat pada waktu itu tetapi juga dapat
dijadikan acuan untuk memprediksi aktivitas dalam jangka panjang.
2.2. Signifikansi Penelitian
Salah satu isu nasional dalam penanganan bencana yang diakibatkan oleh
meningkatnya aktivitas gunungapi adalah terbatasnya data yang diperoleh baik
secara kuantitas maupun secara kualitas. Untuk mendapatkan informasi yang
akurat dan komprehensif tentang aktivitas gunungapi, diperlukan suatu sarana
yang dapat menggambarkan proses/aktivitas gunungapi secara menyeluruh baik
yang melibatkan pendeteksian phenomena di permukaan seperti getaran atau
deformasi maupun pendeteksian informasi tentang struktur tubuh gunungapi
secara menyeluruh. Pemetaan struktur bawah permukaan gunungapi yang
menyeluruh merupakan hal yang sangat penting untuk mengetahui proses yang
terjadi di dalam tubuh gunungapi itu sendiri. Dengan menganalisa proses dan
aktivitas yang terjadi pada tubuh gunungapi, diharapkan dapat memberikan
informasi tentang kondisi aktivitas gunungapi aat itu.
Diperlukan suatu metoda lain yang dapat memberikan informasi secara
akurat dan lebih konprehensif dari aktivitas gununga api. Metoda elektromagnetik
merupakan metoda alternatif untuk memantau aktivitas gunungapi. Dari segi
pemodelan, diperlukan suatu metodologi dan teknik yang dapat meminimalisasi
adanya efek efek yang dianggap sebagai nois seperti efek distorsi galvanik
(galvanic distortion) yang biasa terjadi pada data elektromagnetik khususnya data
magnetotellurik. Dengan melakukan pengembangan baik dari segi pemanfaat
teknologi maupun pengembangan teknik pemodelan, diharapkan data yang
diperoleh tidak saja berguna untuk saat itu (real time) tetapi juga dapat digunakan
untuk mempelajari aktivitas gunug api di waktu
yang akan datang sehingga
penanganan bencana dapat dilakukan lebih awal yang pada akhirnya akan
mengurangi dampak negatif dari aktivitas gunungapi.
2.3. Tujuan Penelitian
Tujuan dilaksanakannya penelitian ini adalah
1. Memanfaatkan metoda elektromagnetik dan metoda magnetik dalam
memantau aktivitas gunungapi di Indonesia.
7
2. Mengembangkan pemodelan elektromagnetik untuk memetakan struktur
resistivitas bawah permukaan didaerah gunungapi.
3. Melalui kerjasama dengan instansi terkait (Direktorat Vulkanologi), akan
menyediakan data/inofrmasi yang lebih baik dan akurat tentang aktivitas
gunungapi yang selanjutnya dapat dijadikan untuk keperluan MITIGASI
BENCANA ALAM di Indonesia
2.4. TINJAUAN PUSTAKA
Pemantauan aktivitas gunungapi akan lebih efektif dan bermanfaat jika
data yang diperoleh tidak saja menggambarkan aktivitas pada saat itu tetapi juga
bisa memprediksi aktivitas gunungapi dalam jangka panjang. Beberapa metoda
yang sejak dulu dan sekarang digunakan untuk mengetahui aktivitas gunungapi
diantaranya adalah metoda seismik, metoda GPS, metoda satelit. Metoda Seismik
adalah metoda yang digunakan dengan melakukan pemantauan getaran yang
ditimbulkan oleh aktivitas gunungapi. Peningkatan aktivitas gunungapi dicirikan
oleh makin tinggi dan seringnya getaran yang terjadi. Alat yang digunakan pada
metoda ini berupa alat seismograf yang dapat merekam data getaran yang
ditempatkan di daerah sekitar gunungapi. Sedangkan metoda GPS adalah
metoda yang memanfaatkan perubahan/deformasi permukaan tanah yang terjadi
sebagai akibat aktivitas gunungapi. Metoda metoda tersebut pada umumnya
memanfaatkan phenomena yang terjadi pada saat aktivitas gunungapi meningkat.
Selain itu, dalam metoda tersebut, data yang diperoleh merupakn sinyal yang
terekam dipermukaan tanpa melibatkan secara langsung informasi proses dalam
tubuh gunungapi itu sendiri.
Struktur bawah permukaan gunungapi sangat kompleks. Struktur ini dapat
di pelajari dalam berbagai parameter fisis misalnya resistivitas/konduktivitas,
massa jenis, sifat magnetik, data kecepatan gelombang seismik, dan lain lain.
8
Perubahan resistivitas terhadap aktivitas gunungapi
Diantara parameter fisis tersebut, resistivitas merupakan parameter yang
dapat dijadikan acuan dalam memantau aktivitas gunungapi. Hal ini disebabkan
nilai resistivitas/konduktivitas batuan berhubungan dengan kandungan lempung
(clay). Hubungan konduktivitas dengan kandungan lempung (clay) dirumuskan
dalam persamaan berikut (Waxman and Smits, 1968) :
(1)
adalah konduktivitas batuan, F adalah formation factor, w adalah kondutivitas
air dan  adalah konduktivitas yang berhubungan dengan perpindahan kation
pada lempung.
Pada gunungapi yang bertipe preatik, peningkatan aktivitas gunungapi
berhubungan erat dengan kandungan lempung (clay) sebagai akibat menaiknya
temperatur
dibawah
permukaan.
Hubungan
antara
temperatur
dengan
pembentukan lempung (clay) dapat ditemukan dalam beberapa referensi seperti
di daerah Salton Sea, California (Jennings and Thompson, 1986), New Zeeland
(Harvey and Browne, 1991), Nesjavellir, Iceland (Arnason et al, 2000),
Awibengkok, Indonesia (Gunderson et al, 2000), Gunungapi Kusatsu-Shirane,
Japan (Kurasawa, 1993). Keberadaan lempung (clay) dalam struktur gunungapi
dan hubungannya dengan sebaran resistivitas dapat dijumpai pada referensi
Nurhasan et al., 2006.
Dengan demikian, pemetaan daerah konduktif di daerah gunungapi
merupakan langkah yang sangat penting untuk menganalisa kandungan lempung
dan hubungannya dengan aktivitas gunungapi. Untuk tujuan ini, metoda
elektromagnetik merupakan metoda yang paling efektif untuk digunakan, karena
parameter yang digunakan adalah resistivitas dan kemampuannya untuk
mendeteksi dan memetakan kontras konduktivitas sampai kedalaman sekitar 3 km
dari permukaan.
9
Perubahan sifat magnetik batuan terhadap aktivitas gunungapi
Meningkatnya aktivitas gunungapi dicirikan dengan naiknya temperatur
yang berasal dari magma menuju ke permukaan. Batuan bawah permukaan
gunungapi akan mengalami perubahan magnetisasinya ketika temperatur yang
melewatinya
mengalami
magnetisasinya
menjadi
perubahan.
bahan
yang
Bahan
magnetik
magnetisasinya
akan
berubah
berkurang
jika
temperaturnya menaik. Dengan demikian, perubahan sifat magnetik batuan di
daerah gunungapi aktif akan memberikan informasi tentang tingkat aktivitas
gunungapi tersebut. Semakin meningkat aktivitasnya, maka temperaturnya akan
semakin tinggi yang menyebabkan sifat magnetik batuannya akan cenderung
kearah sifat diamagnetik (Yamazaki et al., 1990, Koike et al., 2003). Perubahan
sifat magnetik batuan ini akan diukur melalui survey magnetik yang akan
dilakukan secara berkala dalam periode tertentu sehingga dapat diperoleh
perubahan sifat magnetiknya.
Pada tahun 1990, Yamazaki et al. (1990), telah melakukan pengukuran
geomagnetic di gunungapi Kusatsu, Jepang secara berulang dan diperoleh hasil
bahwa terdapat hubungan yang erat antara data magnetik dengan meningkatnya
aktivitas gunungapi tersebut.
Beberapa hasil pemodelan elektromagnetik dan hubungannya dengan
gunungapi yang sudah dan sedang kami kembangkan dalam berbagai penelitian
diantaranya :
I. Publikasi Ilmiah
1. Nurhasan , Y. Ogawa , N. Ujihara, S.B. Tank , Y. Honkura, S. Onizawa,, T.
Mori , and M. Makino, 2006, Two electrical conductors beneath KusatsuShirane volcano, Japan, imaged by audiomagnetotellurics and their
implications for hydrothermal system, Earth Planets Space, vol. 53, 1053 1059.
2. Nurhasan , Y. Ogawa, N. Ujihara , S.B. Tank , Y. Honkura , Teruo
Yamawaki, maging of Hydrothermal System in Kusatsu-Shirane Volcano,
10
Japan, using Three Dimensional Magnetotelluric Inversion, The IAGA 11th
Scientific Assembly, Sopron, August 23-30, 2009.
3. Nurhasan , D. Sutarno , Y. Ogawa , D. Sugiyanto , M Irwan, F. Kimata,
Takeo Ito, Agustan, Investigation of Sumatra Fault based on
Magnetotelluric and GPS Measurements, The IAGA 11th Scientific
Assembly, Sopron, August 23-30, 2009.
4. Nurhasan , D. Sutarno, W. Srigutomo, E J Mustopa, U. Fauzi,Y. Ogawa,
Three-Dimensional Resistivity Structure of Papandayan Volcano, Indonesia
derived from Magnetotelluric Data, Pertemuan Ilmiah Tahunan Himpunan
Ahli Geofisika Indonesia (PIT HAGI), Yogyakarta, 9 – 12 November 2009
5. Nurhasan , D. Sutarno, Y. Ogawa, Dimensionality Analysis of Resistivity
Structure of Volcanic Zone from Magnetotelluric Data, Pertemuan Ilmiah
Tahunan Himpunan Ahli Geofisika Indonesia (PIT HAGI), Yogyakarta, 9 –
12 November 2009.Geomagnetism Meeting, Tokyo, 2009
6. Pengembangan metoda Robust pada impedansi magnetotelluric (Sutarno,
D., 2006).
II. Kelengkapan Peralatan
Untuk keperluan survey dan pemodelan, laboratorium yang berada di KK
Fisika Sistem Komplek memiliki fasilitas lengkap untuk menunjang kelangsungan
Penelitian ini, diantaranya peralatan magnetik, resistivitas dan beberapa komputer
dengan momeri yang cukup besar.
III. Hasil penelitian di Gunungapi Papandayan berdasarkan resistivitasnya
diperlihatkan pada gambar dibawah ini.
11
Utara
Kawah
Gambar 1. Distribusi resistivitas pada daerah gunungapi Papandayan
(Hasil penelitian KNRT 2008-2009)
3. METODOLOGI
Metodologi yang akan digunakan dalam penelitian ini meliputi :
1. Aspek Pemanfaatan metoda elektromagnetik
Pengambilan data elektromagnetik sudah kami lakukan dapa penelitian
penelitian sebelumnya sehingga pada penelitian ini, pengambilan data
elektromagnetik
merupakan
data
untuk
mengetahui
sejauh
mana
perubahannya.
2. Aspek pemanfaatan metoda magnetik
Survey metoda magnetik akan dilakukan secara berkala untuk mengetahui
perubahan yang terjadi sebagai akibat meningkatnya/menurunkan akktivitas
gunungapi.
Pengukuran akan dilakukan di gunungapi Papandayan, Garut
karena gunungapi ini baru meletus dan masih dalam proses aktif sehingga
diharapkan dapat dilihat perubahan aktivitasnya.
3. Aspek Pemodelan Elektromganetik dan Magnetik
Fokus
utama
pada
penelitian
ini
adalah
pembuatan
pemodelan
elektromagnetik yang memiliki tingkat kecepatan hitung dan keakurasian tinggi.
Untuk mendapatkan hasil yang lebih baik dalam rangka tersedianya model
12
awal
yang
lebih
mendekati
model
sebenarnya,
maka
diperlukan
pengembangan pemodelan baik 1 dimensi maupun 2 dimensi. Pada tahap
kedua ini, pemodelan difokuskan :
a. Penyempurnaan pemodelan elektromagnetik yaitu :
i. Pemodelan 2 dimensi sebagai sarana untuk mendapatkan masukan
model awal untuk pemodelan 3 dimensi
ii. Pemodelan 3 dimensi
b. Pengujian Pemodelan dengan data sintetik
c. Aplikasi unutuk data lapangan (data MT)
d. Analisa dan interpretasi hasil pemodelan
Urutan dalam penelitian ini sebagai berikut :
1. Studi Literatur , dikhususkan pada data data pendukung untuk daerah
gunungapi yang akan diteliti.
2. Penyempurnaan pemodelan elektromagnetik yang meliputi :
o Pemodelan 1 dan 2 dimensi
o Pemodelan tiga dimensi.
3. Pengetesan program pemodelan tersebut dengan menggunakan data sintetik
4. Melakukan simulasi monitoring gunungapi dengan menggunakan data sintetik
5. Pengambilan data ke-1
6. Pemetaan resistiivtas dan sifat magnetik bawah permukaan gunungapi
11. Dari 3 data yang berbeda waktu, akan di buat monitoring gunungapi yang
akan dikombinasikan dengan data geofisika lain.
Aspek penelitian tersebut digambarkan pada diagram dibawah ini.
13
MITIGASI BENCANA ALAM
MONITORING GUNUNGAPI
METODA SAAT INI
Sumber Informasi :
Phenomena yang
terdeteksi
dipermukaan bumi
(getaran, deformasi )
METODA YANG DIUSULKAN
Sumber Informasi : Proses
aktivitas gunung api secara
komprehensif dan terintegrasi
Perubahan temperatur
Pemodelan
Elektromagnetik dan
Magnetik
Perubahan
resistivitas :
Perubahan sifat
magnetik
Metoda Magnetik
Metoda
Elektromagnetik
Gambar 2. Diagram kerangka konseptual monitoring gunungapi dengan metoda
EM dan Magnetik
14
4. DAFTAR PUSTAKA
Cagniard, L., Basic theory of the magnetotelluric method of geophysical
prospecting. Geophysics, 18, p.605, 1953
Groom, R. W. and R.C. Bailey, Decomposition of magnetotelluric impedance
tensor in the presence of local three-dimensional galvanic distortion, J.
Geophys. Res., 94, 1913–1925, 1989.
Hasanuddin, Z.A, et al., Studi Deformasi Gunung Kelut Dengan Metode Survei
GPS , Prosiding PIT HAGI ke – 26, Jakarta, 2001
Hohmann, G..W., Three-dimensional EM Modeling, Geophysical Survey , 6, 27-53,
1983.
Kurasawa, T., Problem with the drilling of geothermal well in the south of Mt.
Kusatsu-Shirane, Gunma Prf., J. Japan Geothermal Energy Assoc., 30, 1-23,
1993 (in Japanese with English Abstract).
Muller A, and V. Haak, 3-D modeling of the deep electrical conductivity of Merapi
volcano (Central Java): integrating magnetotellurics, induction vectors and
the effects of steep topography, J. Volcano. Geotherm. Res., 138 (3-4): 205222, 2004.
Nurhasan , Y. Ogawa , N. Ujihara, S.B. Tank , Y. Honkura, S. Onizawa,, T. Mori ,
and M. Makino, Two electrical conductors beneath Kusatsu-Shirane volcano,
Japan, imaged
by audiomagnetotellurics and
their implications for
hydrothermal system, Earth Planets Space, 2006, vol. 53, 1053 - 1059.
Ogawa, Y., On two-dimensional modeling of magnetotelluric field data, Surv.
Geophys., 23 (2-3), 251-273, 2002.
Ogawa, Y., N. Matsushima, H. Oshima, S. Takakura, M. Utsugi, K. Hirano, M.
Igarashi, and T. Doi, A resistivity cross-section of Usu volcano, Hokkaido,
Japan, by audiomagnetotellurics soundings, Earth Planets Space, 50, 339346, 1998.
Ogawa, Y. and T. Uchida, A two-dimensional magnetotelluric inversion assuming
Gaussian static shift, Geophys. J. Int., 126, 69–76, 1996.
Shi,
X.,
H.
Utada,
J.
Wang,
W.
Siripunvaraporn,
Three-dimensional
magnetotelluric forward modeling using vector finite method combined with
divergence correction based on the magnetic fields (VFEH++),
15
Siripunvaraporn, W., G. Egbert, An efficient data-subspace inversion method for 2D magnetotelluric data, Geophysics, 65,3, 791-803, 2000.
Sutarno,
D.,
(2006).
Development
of
Robust
Magnetotelluric
Impedance
Estimation, Indonesian Journal of Physics, 16, no. 3, 81 - 91
Srigutomo, W., Sutarno, D. and Harja, A. (2006). 2-D Magnetotellurics numerical
modeling using the boundary element method, International Conference on
Mathematics and Natural Sciences, Bandung .
Waxman, M.H., L.J.M. Smits, Electrical Conductivities in Oil-Bearing Shaly Sands,
Society of Petroleum Engineers Journal, 243, 107-122, 1968
Saito, A., Experimental study on the demagnetization of rocks under interaction
with acid geothermal fluid, Master thesis, Tokyo Institute of Technology, 42pp,
(in Japanese) 2003
Yamazaki, A., Churei,M., Tsunomura, S., and Nakajima, S., Analysis of the
variation of geomagnetic total force at Kusatsu-Shirane volcano: the
remarkable changes in the geomagnetic total force in 1990 and the estimated
thermal demagnetization model, Mem. Kakioka Mag. Obs., 24, 2, 53-66,
1992. (in Japanese with English abstract).
5. Target output (keluaran) Riset
No.
Nama/Jenis Output
1. Jurnal Nasional ber-referee/terakreditasi
2.
Prosiding Konferensi Internasional
:
Jumlah
2
1
16
6. JADWAL PENELITIAN
KEGIATAN
1.
2.
6.
7.
6.
7.
6.
7.
5.
Studi Literatur
Pemodelan elektromagnetik dan magnetik
Akuisisi data ke-1 Gunungapi
Prosesing data ke -1 Gunungapi
Pembuatan Pemodelan dan
Simulasi monitoring Gunungapi dengan
data sintetik
9. Interpretasi data secara keseluruhan
10. Laporan kegiatan
BULAN
KE1 2 3 4 5 6 7
8 9 10
17
7. PETA JALAN (ROAD MAP) PENELITIAN
Tahap
Pengembangan
2006 - 2010
Tahap Inisiasi
2000 - 2005
Inventarisasi Software –
software yang sudah di
buat meliputi :
- Pemodelan kedepan
1D dan 2D
elektromganetik (MT
dan CSAMT
- Teknik teknik
pengolahan data
-
-
-
Pengembangan
pemodelan
kearah
inversi baik 1D dan 2D
Elektromganetik
Pengembangan
Pengambilan
dan
Pengolahan
data
elektromagnetik
Pembuatan
pemodelan 3 dimensi
elektromagnetik
Tahap Lanjut
2010 - 2020
-
-
-
Pengembangan
pemodelan 3 dimensi
baik forward maupun
inversi
Pembuatan software
secara terintegrasi
yang meliputi 1D, 2D
dan 3 D
Pengembangan
pengolahan data
elektromganetik
Menghasil software software yang terintergarsi dalam bidang elektromagnetik baik untuk
pemodelan maupun pengolahan data
APLIKASI METODA ELEKTROMAGNETIK DAN GEOFISIKA LAINNYA
PADA BEBERAPA KASUS YAITU :
1. BENCANA ALAM (GUNUNGAPI, KEGEMPAAN, LONGSOR)
2. GEOTHERMAL
18
8. USULAN BIAYA RISET
8.1 REKAPITULASI BIAYA :
No.
1.
2.
3.
4.
5.
Keterangan
Dana
Belanja Pegawai
Belanja Barang
Honor Pihak Ke-3
Perjalanan
Sewa alat, jasa layanan, dal lain lain
18.125.000,3.000.000,12.000.000,15.500.000,1.375.000,-
Jumlah
Rp 50.000.000,-
8.2 RINCIAN BIAYA :
8.2.1. Belanja pegawai
No.
1.
2.
Pelaksana Kegiatan
Peneliti Utama
Anggota Peneliti
Jumlah
Orang
1
2
Honor per
Jumlah
Jumlah
Jam
Jam/Bulan Bulan/Tahun
27.500
25
10
22.500
25
10
Jumlah total biaya honor (Rp)
Jumlah Biaya
(Rp)
6.875.000,11.250.000,18.125.000,-
8.2.2. Belanja barang
No.
1.
2.
Peralatan/Bahan
Biaya Satuan
(Rp)
Jumlah Biaya
(Rp)
2.000.000,-
2.000.000,-
1 SET
1.000.000,Jumlah total biaya barang (Rp)
1.000.000,3.000.000,-
Volume
Keperluan Survey (Accu, Peta,
Batterai, dll)
ATK
Satuan
1 SET
8.2.3. Belanja jasa
a. Honor pihak ketiga non PNS ITB dan ITB-BHMN atau asisten mahasiswa
Jumlah Honor per
Jumlah
Jumlah
Jumlah Biaya
No.
Pelaksana Kegiatan
Orang
Jam
Jam/Bulan Bulan/Tahun
(Rp)
1. Mahasiswa
2
15.000,20
10
6.000.000,2. Tenaga penunjang
4
10.000,15
10
6.000.000,Jumlah total biaya honor (Rp) 12.000.000,b. Perjalanan
No.
1.
2.
Jumlah Biaya
(Rp)
Survey untuk pengambilan data ke gunungapi, selama 15 hari dengan rincian :
Tujuan
1.1 Sewa mobil (+bensin) 15 hari x Rp.
500.000
1.2 Akomodasi 4 orang x 15 hari x Rp.
100.000
Mengikuti Pertemuan Ilmiah
nasional/internasional
Volume
Biaya Satuan (Rp)
15 hari
500.000,-
7.500.000,-
15 hari
400.000,-
6.000.000,-
2 orang
1.000.000,-
2.000.000,-
Jumlah total biaya perjalanan (Rp)
15.500.000,-
19
c. Sewa Alat, Jasa Layanan dan Lain-lain
No.
1.
2.
Nama Alat/Jasa Layanan
Volume
Biaya Satuan (Rp)
Laporan dan Penggandaan
1 set
875.000,Rapat koordinasi
5x
100.000,Jumlah total biaya sewa alat, jasa layanan, dll. (Rp)
Jumlah Biaya
(Rp)
875.000,500.000,1.375.000,-
II. Sarana
(1) Laboratorium
Laboratorium Fisika Bumi ITB dilengkapi dengan peralatan penelitian yang
lengkap untuk menunjang kegiatan penelitian ini.
(2) Peralatan utama:
Peralatan utama yang dimiliki oleh Laboratorium Fisika Bumi adalah
No.
1
2
Nama Alat
Kegunaan
CSAMT unit, GDP16 Untuk
pengukuran
Zonge
bawah permukaan
Sensor Magnetik
Untuk
Keterangan
resistivitas
pengekuran
medan
magnetik
3
PC
Untuk pengolahan dan pemodeln
numerik
III. Dukungan pada Pelaksanaan Penelitian
Pada saat ini sudah disusun 2 buah makalah ilmiah Internasional dan 1 makalah
Nasional yaitu :
1. Nurhasan , D. Sutarno, Y. Ogawa , N. Ujihara, S.B. Tank , Y. Honkura, Three
Dimensional Electromagnetic Imaging of Kusatsu-Shirane Volcano and Its
Implications for Hydrothermal System (submit to Geophysical Research Letter,
2010)
2. Nurhasan , D. Sutarno , Y. Ogawa , D. Sugiyanto , M Irwan, F. Kimata, Takeo
Ito, Agustan, Investigation of Sumatra Fault based on Magnetotelluric and GPS
Measurements (submit to Earth and Planetary Sciences Journal )
3. Nurhasan , D. Sutarno, W. Srigutomo, E J Mustopa, U. Fauzi,Y. Ogawa,
Three-Dimensional Resistivity Structure of Papandayan Volcano, Indonesia
derived from Magnetotelluric Data (submit to Indonesian Physics Journal )
Ketiga makalah tersebut ditunjukan pada bagian lampiran :
20
9.
CV TIM PENELITI
CURRICULUM VITAE
A. Personal Data
1. Name and title
2. Unit in ITB
3. Office address
4. Education
Bachelor (S1)
Master (S2)
Doctor (S3)
B. Position history
1999 – Now
Sciences, ITB
: Nurhasan, Ph.D
: Physics of Complex System, Faculty of Mathematics and
Natural Sciences, ITB
: Jl. Ganesha 10 Bandung 40132
:
: Physics Department, Bandung Institute of Technology
: Earth Science, Physics Department, Bandung Institute of
Technology
: Earth Sciences, Tokyo Institute of Technology, Japan
(Electromagnetic induction for Volcano and Geothermal)
:
: Lecturer/Researcher at Faculty of Mathematics and Natural
Publications (International and Domestic)
4. Nurhasan , Y. Ogawa , N. Ujihara, S.B. Tank , Y. Honkura, S. Onizawa,, T. Mori ,
and M. Makino, 2006, Two electrical conductors beneath Kusatsu-Shirane volcano,
Japan, imaged by audiomagnetotellurics and their implications for hydrothermal
system, Earth Planets Space, vol. 53, 1053 - 1059.
5. Nurhasan , D. Sutarno, Y. Ogawa , N. Ujihara, S.B. Tank , Y. Honkura, Three
Dimensional Electromagnetic Imaging of Kusatsu-Shirane Volcano and Its
Implications for Hydrothermal System (submit to Geophysical Research Letter,
2010)
6. Hashimoto, T., T. Mogi, Y. Nishida, Y. Ogawa, N. Ujihara, M. Oikawa, M. Saito,
Nurhasan, S. Mizuhashi, T. Wakabayashi, R. Yoshimura, A. W. Hurst, M. Utsugi,
Y. Tanaka, Self-potential studies in volcanic areas (5) -Rishiri, Kusatsu-Shirane,
and White Island-, J. Fac. Sci. Hokkaido Univ., Ser. VII, 12, 2, 97-113, 2004
7. Nurhasan, Y. Ogawa , N. Ujihara , S.B. Tank, T. Wakabayashi and S. Onizawa,
Resistivity structure of Kusatsu-Shirane Volcano imaged by audio-magnetotelluric
observations, Kusastu Report, 2004.10
International/Domestic Conferences
1. Nurhasan , Y. Ogawa, N. Ujihara , S.B. Tank , Y. Honkura , Teruo Yamawaki,
maging of Hydrothermal System in Kusatsu-Shirane Volcano, Japan, using Three
Dimensional Magnetotelluric Inversion, The IAGA 11th Scientific Assembly, Sopron,
August 23-30, 2009.
2. NURHASAN , D. Sutarno , Y. Ogawa , D. Sugiyanto , M Irwan, F. Kimata, Takeo
Ito, Agustan, Investigation of Sumatra Fault based on Magnetotelluric and GPS
Measurements, The IAGA 11th Scientific Assembly, Sopron, August 23-30, 2009.
21
3. Nurhasan , D. Sutarno, W. Srigutomo, E J Mustopa, U. Fauzi,Y. Ogawa, ThreeDimensional Resistivity Structure of Papandayan Volcano, Indonesia derived from
Magnetotelluric Data, Pertemuan Ilmiah Tahunan Himpunan Ahli Geofisika
Indonesia (PIT HAGI), Yogyakarta, 9 – 12 November 2009
4. Nurhasan , D. Sutarno, Y. Ogawa, Dimensionality Analysis of Resistivity Structure
of Volcanic Zone from Magnetotelluric Data, Pertemuan Ilmiah Tahunan
Himpunan Ahli Geofisika Indonesia (PIT HAGI), Yogyakarta, 9 – 12 November
2009.Geomagnetism Meeting, Tokyo, 2009
5. Y. Ogawa , Nurhasan, S.B. Tank, N. Ujihara, Y. Honkura, & T. Yamawaki ,
Imaging a Vapor Reservoir at Kusatsu-Shirane Volcano, By Three-Dimensional
MT Inversion and Relocated Micro-Earthquakes, Geomagnetism Meeting, Tokyo,
2009
6. Enjang J M, Nurhasan , Doddy Sutarno, Wahyu Srigutomo, Two-dimensional
Electromagnetic Image of Kamojang Geothermal Field, Indonesia by CSAMT Data,
( accepted to be presented on 19th electromagnetic induction workshop, Beijing ,
China, 23 – 29 October 2008)
7. Nurhasan , Y. Ogawa , Doddy Sutarno, Didik Sugiyanto, Imaging fault zone by
MT Method at Sumatra area in Indonesia ( accepted to be presented on 19th
electromagnetic induction workshop, Beijing , China, 23 – 29 October 2008)
8. Nurhasan , Y. Ogawa , N. Ujihara, S.B. Tank , Y. Honkura, Geothermal system of
a phreatic eruption environment under Kusatsu-Shirane volcano, implied by three
dimensional magnetotelluric modeling, IUGG Meeting, Perugia, Italy, 2 – 13 July,
2007
9. Mogi T, Nurhasan, Y. Ogawa, Djedi, W.S , Resistivity structure at damage area of
the 2006 mid Java earthquake, IUGG Meeting, Perugia, Italy, 2 – 13 July, 2007
10. Nurhasan , Y. Ogawa , N. Ujihara, S.B. Tank , Y. Honkura, Three-dimensional
electromagnetic image of Kusastu-Shirane volcano and its implications for
hydrothermal system, 18th induction workshop, Barcelona , Spain, 2006.9.17-23.
11. Kasaya, K, Y. Ogawa, Nurhasan, N. Ujihara, F. Kimata, Fluid detection using
AMT survey on the seismogenic zone around the eastern foot of Mt. Ontake, central
Japan, IAGA General Assembly, Toulouse, France, 2005.7.18-29
12. Ogawa, Y, Nurhasan, N. Ujihara, S. Onizawa, Electromagnetic imaging of seismic
LP resonator at Kusatsu-Shirane volcano, Japan, IAGA General Assembly,
Toulouse, France, 2005.7.18-29
13. Nurhasan , Y. Ogawa , N. Ujihara , S.B. Tank, and S. Onizawa, Kusatsu-Shirane
volcano imaged by audio magnetotelluric method, 17th induction workshop,
Hyderabad, India, 2004.10.
14. Ogawa, Y, M. Uyeshima, Nurhasan, K. Takahashi, S. Koyama, T. Ogawa,
Weerachai Siripunvaraporn, R. Yoshimura, H. Satoh, Magnetotelluric evidence for
groundwater loss as a cause of continuous SO2 degassing at Miyakejima volcano,
Japan, 17th induction workshop, Hyderabad, India, 2004.10.
15. Nurhasan,Yasuo Ogawa, Naoto Ujihara, Electromagnetic images of KusatsuShirane volcano and its implications for hydrothermal system, Conductive
Anomaly Meeting, University of Tokyo, Japan, December 2005.
16. Nurhasan ,Yasuo Ogawa, Naoto Ujihara, Electromagnetic Image of seismic LP
resonator at Kusatsu-Shirane volcano, Volcano Meeting 、 Sapporo, Japan,
October 2005
17. Nurhasan , Yasuo Ogawa, Naoto Ujihara, Onizawa Shinya, Audiomagnetotelluric
22
study of the geothermal system of Kusatsu-Shirane volcano, Geomagnetism
Meeting, Kyoto, Japan, September 2005.
Research project activities:
No.
Research / Project
Year
Position
1
Pengembangan Pemodelan Elektromagnetik
”Audio Magnetotelluric” Tiga Dimensi
sebagai Sarana Informasi Alternatif untuk
Monitoring Gunungapi ,
PROGRAM INSENTIF RISET DASAR,
KNRT.
Image of subduction zone in Aceh region,
Sumatra, Indonesia
using magnetotelluric
method, Joint research Unsyiah – ITB - Tokyo
Institute of Technology, Japan
Repeating magnetotelluric measurement in
Kusatsu-Shirane volcano, Japan and its
implication to geothermal system, Visiting
Researcher at Tokyo Institute of Technology,
Japan
Electromagnetic study in Bantul-Yogyakarta to
delineate shallow soft sediment and its
implication in earthquake distribution, Joint
research LIPI – Hokkaido University
EARTH : How to build habitable planets ?, part
of The 21st Century CEO Program, Tokyo
Institute of Technology, Japan
2008 2009
Principal
investigator
2008 2009
Researcher
2007
Researcher
2006
Member
2005
Research
Assistant
2
3
4
3
Bandung, 30 September 2010
Dr. NURHASAN
23
CURRICULUM VITAE
1.
Name
:
2.
Place and date birth :
Bandung, January 9, 1953
3.
Current Position
Lecturer/Researcher
:
Doddy Sutarno, Ph. D.
4.
Educational experience:
1992 Ph. D. (in Geophysics) from Macquarie University, Sydney, NSW,
Australia.
1983 M.Si. (in physics) from Bandung Institute of Technology, Bandung.
1979 Sarjana (in physics) from Bandung Institute of Technology, Bandung
5.
Research experience:
No
Project Name
Period
Position
1
Proyek DIP-ITB:
Penyelidikan Air Tanah dengan Metoda
“Geoelectrics Plurry direction” di Daerah
Gunung Kidul, Jawa Tengah
1981-1982
Angggota
2
Proyek DIP-ITB:
Penentuan Elastisitas Campuran Bahan Padat
dengan Gelombang Ultra Sonic
1982-1983
Ketua
3
Proyek DPPM:
Pemodelan Konduktivitas Batuan Berdasarkan
Teori Perkolasi
1982-1983
Anggota
4
Proyek DIP-ITB:
Aplikasi Data Seismogram Gempa Bumi untuk
Studi Regional
1983-1984
Anggota
5
Proyek PPPG:
Penyelidikan Gaya Berat dan Geolistrik secara
terpadu di Daerah Cimareme
1983-1984
Anggota
6
Proyek DPPM:
Penelitian Chemisorpsi Logam
1984-1985
Anggota
7
Proyek DPPM:
Pengembangan Metoda Polarisasi Terimbas dan
TURAM
1984-1985
Ketua
8
Seismic survey at Mora, Western Australia.
1987
Anggota
24
9
CSAMT Survey at Queenstown, Tasmania
1988
Anggota
10
MT survey at north Melbourne, Australia
1989
Anggota
11
Proyek OPF-ITB:
Pengembangan Metoda Seismik Refraksi Vertikal
1992-1993
Ketua
12
Proyek Penelitian Basic Science I:
Inversi Magnetotelurik 2-D
1992-1993
Ketua
13
Proyek Penelitian Basic Science II:
Pemodelan Elemen Hingga Magnetotelurik 2-D
1993-1994
Ketua
14
Proyek Penelitian Basic Science III:
Pemodelan Magnetotelurik 2-D dengan Metode
Persamaan Integral
1994-1995
Ketua
15
Riset Unggulan Terpadu I:
Studi Evolusi Tektonik dengan Metoda Geofisika
Terpadu untuk Menyelidiki Potensi Sumber Alam
di Daerah Lengguru, Irian Jaya
1993-1996
Anggota
16
Riset Unggulan Terpadu III:
Penyelkidikan Sungai Bawah Tanah dengan
Metoda Elektromagnetik-VLF dan Gaya berat di
Daerah Gunung Kidul, Jawa Tengah
1995-1998
Anggota
17
Riset Unggulan Terpadu (RUT) VI:
Aplikasi Teknologi Elektromagnetik dan Simulasi
Numerik dalam Pengembangan Energi Gunung
Api Sebagai Wahana Energi Alternatif di Masa
Mendatang
1998-2001
Ketua
18
Hibah Bersaing X:
Aplikasi Metoda CSAMT untuk Monitoring
Aktivitas Gunung Api
2002-2003
Anggota
19
Program Riset ITB:
Estimasi robust Fungsi IMPedansi CSAMT
berdasarkan estimator-M
2006-2007
Ketua
20
Proyek Riset KK- ITB:
Estimasi robust Fungsi IMPedansi CSAMT
berdasarkan estimator-M TAHAP II
2007-2008
Ketua
2007-2009
Anggota
21
Program Intensif Riset Terapan-KNRT:
Aplikasi teknologi elektromagnetik “Controlled
Source Audio Magnetotelluric (CSAMT)” untuk
25
Eksplorasi Panas Bumi Sebagai Sumber Energi
Alternatif
6. Selected publications and presentations
Sutarno, D. (2010) Robust Magnetotelluric Impedance Estimation, Accepted for The 4th
Asian Physics Symposium, Bandung, Indonesia.
Nurhasan, D. Sutarno, W. Srigutomo, E.J. Mustopa, U. Fauzi, Y. Ogawa (2009). Three
Dimensional Resistivity Structure of Papandayan Volcano, Indonesia derived
from Magnetotelluric Data, The 34th HAGI Annual Convention, Exhibition and
2nd Geophysics Education Symposium Yogyakarta, November 2009.
Nurhasan, D. Sutarno, Y. Ogawa (2009). Pendugaan Struktur Resistivitas Cekungan
Bandung Bagian Timur, Menggunakan Metode CSAMT Pendekatan Gelombang
Bidang, The 34th HAGI Annual Convention, Exhibition and 2nd Geophysics
Education Symposium Yogyakarta, November 2009.
Harja, A., W. Srigutomo2, E.J. Mustofa,D. Sutarno (2009). Pendugaan Struktur
Resistivitas Cekungan Bandung Bagian Timur, Menggunakan Metode CSAMT
Pendekatan Gelombang Bidang, The 34th HAGI Annual Convention, Exhibition
and 2nd Geophysics Education Symposium Yogyakarta, November 2009.
Sutarno, D. (2008). Constrained robust estimation of magnetotelluric impedance functions
based on a bounded-influence regression M-estimator and the Hilbert transform,
Nonlinear Processes in Geophysics, 15, 287-293.
Sutarno, D. and I. Fatrio (2007). Robust M-estimation of CSAMT impedance functions,
Indonesian Journal of Physics, 18:3, 81-85
Sutarno, D. and Fatrio, I. (2007) An application of Robust M-Estimation to CSAMT Data
Processing, Proceeding of the 11th SEGJ Conference, Sapporo, Japan.
Sutarno, D. and I. Fatrio (2007). An Application of robust M-estimation with the Hilbert
transform to CSAMT data processing, Proc. of The 2nd Asian Physics Symposium,
Bandung Indonesia.
Sutarno, D., (2006). Development of Robust Magnetotelluric Impedance Estimation,
Indonesian Journal of Physics, 16, no. 3, 81 - 91
Sutarno, D., (2006). Robust estimation of magnetotelluric impedance functions based on a
bounded-influence regression M-estimator and the Hilbert transform, Geophysical
Research Abstracts, 8, 01612 (Presented in EGU General Assembly, Vienna).
Sutarno, D. (2006). Robust estimation of magnetotelluric impedance functions based on
the regression M-estimator, in “ Geo-hazard and earth-resources in Indonesia”,
Geoforum Bandung V, HAGI.
Fatrio, I., and Sutarno, D. (2006). Robust M-estimation of Controlled Source Audio
Magnetotellurics (CSAMT) Impedance Functions, Proceeding of the International
Conference on Mathematics and Natural Sciences, ISBN:979-3507-91-8, 862-865
Harja, A., Sutarno, D., and Srigutomo, W. (2006). DC-resistivity survey for groundwater
investigation: Case Study in Eastern Bandung, Proceeding of the International
Conference on Mathematics and Natural Sciences, ISBN:979-3507-91-8, 12811283
Srigutomo, W., A. Harja, D. Sutarno, and T. Kagiyama (2006). VLF data analysis through
transformation into resistivity value: application to synthetic and field data,
Indonesian Journal of Physics, 16:4, 83-95
26
Srigutomo, W., Sutarno, D. and Harja, A. (2006). 2-D Magnetotellurics numerical
modeling using the boundary element method, , Proceeding of the International
Conference on Mathematics and Natural Sciences, ISBN:979-3507-91-8, 965-968
Sutarno, D. (2005). Phase-smoothed Robust Estimation of Magnetotelluric impedance
Functions Based on A Bounded-influence Regression M-estimator, Jurnal
Geofisika, 4, no. 2, 10-16.
Bandung, September 30, 2010
Prof. Doddy Sutarno, Ph.D.
27
Nama
: Dr. rer. nat. Sparisoma Viridi
Tempat / Tanggal Lahir : Jakarta / 1 Desember 1973
Pengalaman riset
Pemberi Dana
Ikatan Alumni Institut
Teknologi Bandung
Tempat
Fakultas Matematika dan
Ilmu Pengetahuan Alam,
Institut Teknologi Bandung
Direktorat Pendidikan
Institut Teknologi
Bandung
Riset Kelompok Keahlian
Institut Teknologi
Bandung
Ikatan Alumni Institut
Teknologi Bandung
Institut Teknologi
Bandung
Quality for
Undergraduate
Education (QUE) Project
Nomor riset 20920202
DIKS ITB, LPPM ITB
Departemen Fisika, Fakultas
Matematika dan Ilmu
Pengetahuan Alam, Institut
Teknologi Bandung
Departemen Fisika, Fakultas
Matematika dan Ilmu
Pengetahuan Alam, Institut
Teknologi Bandung
Judul Riset
Brazil-nut effect and its
reverse in two dimension:
registering transition
parameters using molekular
dynamics and building a simple
model
Evaluasi sekunder tematik
matakuliah Fisika Dasar
Tahun
2009
Penyeleksian molekuler secara
mekanika kuantum terhadap
klorofil dan senyawa
turunannya berdasarkan sifat
optoelektronik dalam
pemanfaatan sebagai sel surya
organik
Modelling granular oscillation
induced by chaos using flux
equation and neuratl network
Pemodelan ion dalam kisi
kubik sederhana dalam
pengaruh medan magnetik
luar
Piranti lunak semi intepreter
untuk membantu kuliah Fisika
Matematika
2008
Belajar probabilitas dan
statistika dasar dengan
bantuan halaman web
2002
Publikasi terkini yang terkait
1. Suparno Satira, dan Sparisoma Viridi, "Mekanisme Penyusulan Molekul Antibodi dalam
Larutan Sodium Alginat", Jurnal Nanosains dan Nanoteknologi, Edisi Khusus Agustus, 109111 (2009)
2. Sparisoma Viridi, Suparno Satira, and Freddy P. Zen, "Energy dissipation as function of
vibration frequency for monodispersed granular particles in two chamber system",
Proceeding of Conference on Mathematics and Natural Sciences 2008, Bandung, 28-30
Oktober 2008, Indonesia
3. Sparisoma Viridi, Patrick Grete, and Mario Markus, “A minimal mechanical device displaying
‘bona fide’ stochastic resonance”, Physics Letters A 372 (2008) 1040-1043
4. Sparisoma Viridi, Cooperation between dynamic coefficient of restitution and density ratio
in supporting granular gas oscillation occurrence, Indonesian Journal of Physics 18 (4)
(2007) 103-105
2009
2008
2003
2003
28
5. Sparisoma Viridi, A few granular materials in two horizontal chambers system, Proceedings
of the 2007 Asian Physics Symposium (APS 2007), November 29 – 30, 2007, Bandung,
Indonesia, A.21 (2007)
6. Sparisoma Viridi, Malte Schmick, and Mario Markus, Experimental observations of
oscillations and segregation in a binary granular mixture, Physical Review E 74, 041301
(2006)
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Bandung, September 30, 2010
Dr.rer.nat. Sparisoma Viridi
29
LAMPIRAN BUKTI CAPAIAN OUTPUT TAHUN 2009-2010
MAKALAH 1 : SUBMIT TO Geophysical Research Letter (Int. Journal), 2010
Three Dimensional Electromagnetic Imaging of Kusatsu-Shirane Volcano and Its
Implications for Hydrothermal System
Nurhasan1 , Y. Ogawa2,3 , N. Ujihara2 , S.B. Tank4 , Y. Honkura2
1 Physics Department, Bandung Institute of Technology, Bandung, Indonesia
2 Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo, Japan
3 Volcanic Fluid Research Center, Tokyo Institute of Technology, Tokyo, Japan
4 Kandilli Observatory and Earthquake Research Institute, Boğaziçi University, İstanbul, Turkey
Abstract
Three-dimensional resistivity structure of
Kusatsu-Shirane volcano was imaged by the dense
magnetotelluric measurements (83 sites) using 3D
inversion. To overcome the effect of shallow three
dimensional structure or galvanic distortion, We
have also developed the new methodology of
modeling by applying phase tensor and induction
vector as response functions in the 3d forward
modeling. The three-dimensional topography was
also taken into account in the modeling and twodimensional inversion results of multiple profiles
were used as the initial three-dimensional model.
Based on the final 3d resistivity model, a 200-500 m
thickness disk-shaped conductive zone was observed
in the center of the model beneath the crater.
Interpreting conductor as clay cap of hydrothermal
system, important information was obtained
indicating that two phase reservoir is located in the
high resistivity zone just beneath the clay cap
corresponding to high temperature region. On the
other hand, deeper structure is characterized by a
simple two-dimensional structure with N-S strike,
i.e., the 1km-wide central resistive gap associated
with break down of clay mineral because of high
temperature.
1. Introduction
Kusatsu Shirane volcano is an active
volcano located in central of Japan. This volcano
situated at the south edge of South-East Acr.
Geologically, Kusatsu Shirane volcano was covered
by pyroclastic cone in the summit area surrounded
by lava flow around the summit area [Uto et al.,
1983]. Some evidences such as hot spring, vent and
hydrothermal
manifestation
shown
that
hydrothermal system plays an important role in this
volcano.
. Magnetotelluric method as one of the
electromagnetic methods is the most popular
method for detecting the presence of fluids and
clay minerals in the hydrothermal system.
Application of magnetotelluric method can be
found at active volcanoes [Ogawa and Takakura,
1990; Ogawa et al., 1992, 1998, 1999; DiMaio et
al., 1998; Kagiyama et al., 1999; Fuji-ta et al,
1999; Matsushima et al., 2001; Muller and Haak,
2004; Manzella et al., 2004; Aizawa et al., 2005],
hydrothermal systems [Oskooi et al., 2005;
Pellerin et al., 1996; Caglar and Isseven, 2004],
and active faults [Unsworth, et al., 1999; Tank, et
al., 2003]. In developing a methodology of
modeling, 3-D modeling of magnetotelluric data
has been developed based on using a non free
distortion parameter such as apparent resistivity
[Mogi, 1996; Siripunvaraporn et al., 2000; Sasaki,
2001; Shi et al., 2004]. Muller et al. [2004] have
applied geomagnetic induction vector to examine
lateral variation of resistivity distribution in
volcano region with a small number of site. Our
motivation was inspirited by the fact that the
existence of small local 3d structure will result a
misinterpretation of final results. Therefore, use of
non free distortion parameter is not useful to
remove effect of small 3d structure. Earlier method
applied to reduce effect of 3d small structure such
as Groom-Bailey decomposition [Groom and
Bailey, 1989] and Bahr methods [Bahr, 1991] were
developed. Their methods limited to only twodimensional regional structure because of the use
of non-free distortion parameter such as apparent
resistivity. In 2004, Caldwell et al. [2004]
introduced phase tensor as a parameter which is not
30
138.5400
138.5450
026
029
36.6500
021
020
032
023
20
20
AMT
(Audiomagnetotelluric)
and
Magnetotelluric data were collected in the summit
area in different campaigns from 2001 to 2005. For
the measurements, we used two sets of Phoenix
Geophysics MTU5A system to measure electric and
magnetic fields. AMT measurements was recording
up to five components of electromagnetic fields (two
horizontal electric fields, two horizontal magnetic
fields and vertical magnetic field) in the frequency
range of 1Hz to 1 kHz. On the other hand, MT
survey measured electric fields at each site but used
magnetic fields at base stations to calculate
impedances. Thus, the MT sites have no information
on the magnetic transfer functions. Moreover, the
MT data are available only in a limited frequency
range below 320Hz down to 0.01Hz. The remote
reference technique was also applied to reduce the
noise contamination. The measurement at each site
took an hour to several hours. These differences in
the two datasets should be noted for the compilation.
In total, after the compilations, there are total of 85
sites involving AMT and MT data with a spacing of
approximately 200m covering the peak area
encircling the Mizugama and Yugama craters (See
Figure 1).
138.5350
033
025
038
047
018
062
079
078 075 022 061
36.646
067
0
068
069
017
006 073
058
066
057
037
012
056
076
074
085
035
0
200
400
084
031
011
065
20
Meter
013
044
054
053
003
045
064 052
083
082
600
004
055
008
20
036
36.6380
042
015
028
36.6420
041
059
077
040
034
024
060
071 009 072
070
030
039
005
016
043
2140
Latitude
019
AMT Sites
081
051
027
007
0
2.1. Data Acquisition
138.5300
8
19
2. Data Acquisition and Observed Data
Longitude
138.5250
2060
affected by distortion caused by shallow 3d structure.
In this paper, we applied response functions namely
phase tensor and induction vector that are free
distortion effect to 3d forward modeling. We use
natural electromagnetic fields in the frequency range
between 10 kHz to 0.3Hz. The resistivity model will
be interpreted with the aids of other known
information, such as drill-hole data [Kurasawa,
1993].
During period of 1990s, some peculiar
phenomena were observed indicating increase of
seismic activity [Nakano et al, 2003] and
polarization of change of total magnetic force in N-S
direction [Yamazaki, et. al, 1992]. These phenomena
correspond to enhancement of volcano activity
because of hot fluid activity beneath the summit area.
Other observations, such as geochemical studies
[Hirabayashi et al., 1997; Ohba et al., 1994, 200,
2002; Ohwada et al., 2003; Ossaka et al., 2005],
gravity studies [Makino et al., 2004], and LongPeriod event studies [Nakano et al., 2003] were
undertaken in this volcano. However, none of these
gave quantitative image of the whole geothermal
system of the volcano. The objective of our research
is to get the detail image of hydrothermal system in
terms of resistivity structure and how its relationship
to hot fluid flow to explain mechanism of
hydrothermal system in this volcano.
010
001
050
080
X
Seismicity
MT Sites
High temperature zone
LP resona tor
Demagnetization source
063
Figure 1. MT and AMT site locations
2.2. Presentation of the observed Data
Different from plotting of phase
tensor defined by Caldwell et al. [2004], in this
paper, we calculated the arctangent of the YYcomponent of the phase tensor as a function of the
coordinate angles (X direction of the rotated frame)
by with 3 degree steps. For the modeling and
analysis, we have applied three representative
frequencies (1, 10, and 100 Hz) by reason that
these frequencies correspond to the skin depth of
our target. Figure 2 shows observed phase tensor
and induction vector used to analyze
dimensionality of the structure. For the frequency
of 100 Hz, the observed phase tensors are
dominated by elliptic phase tensors rather than
circular phase tensors where alignment of major
axes are distributed spatially inconsistently
reflecting the heterogeneous structure at the
corresponding skin depth. The induction vectors
generally point toward the central area, but they
also indicate directional variations reflecting the
existence of some other local conductive anomalies.
Figure 2. Observed data in Phase Tensor and
Induction Vector representations.
On the other hand, at 10Hz, the phase
tensors and the induction vectors show clearly the
circular anomalous structure around summit area.
The existence of 3-D conductive zone at the
shallow part provides an explanation for the
31
consistent directions of the induction vectors.
Evidence of the three-dimensionality around the
summit of Kusatsu-Shirane volcano is also detected
by gravity observation [Makino et al., 2004].
At the frequency of 1 Hz representing
deeper structure, two-dimensionality is very
dominant as exhibited by phase tensors and
induction vectors. Dominant alignment of the long
axis of the ellipse with the east-west direction and
the eastward induction vectors indicate that the
existence of two-dimensional structure with N-S
strike.
Figure 3. Final model of resistivity distribution
obtained from 3D inversion.
3. 3-D Inversion
3-D inversion’s code providing by Wiraacahi
was used to invert overall MT data with a total of 85
sounding. The 7 representative frequencies were
used in this inversion starting from 0.1 To 100 Hz.
The earth model is divided into rectangular blocks
with magnetic field H defines along the block edge.
In this procedures of 3-D modeling process, the total
area of the model 6 km x 6 km x 10 km are divided
into 38 x 44 x 30 grids in x,y,z direction,
respectively with air mesh consist of 7 layers.
Distances between grids are made logarithmically
increased starting from the center of the model.
Homogeneous model was used for the initial model
and the resistivity of Yugama lake water is set to 0.3
m based on the measurement of lake water samples.
4. Result and Interpretation
Based on the final 3-D model shown in
Figure 3, the summit area is characterized by an
additional shallow complexity, compared with the
deeper two-dimensional structure.
Surface structure is dominated by high
resistivity of 10k Ω.m at the eastern part of summit
and 100 Ω.m at the western part of the summit area.
This structure agrees with distribution of lava in
geological structure. Small two conductors (C0b and
C0c in Figure 3) exposed to the surface coincidence
with the locations of the vents and hydrothermal
manifestations.
The main structure of the clay cap of
hydrothermal system was found in the center of the
model at the depth of 200 – 700 m from the surface
(C0a in Figure 4). This conductor ranging of 1- 5
Ω.m was forming an elliptic conductive cap with
major axes of 2 km aligning in north-south
direction. The existence of this conductor is clearly
detected by the induction vectors at frequencies
100Hz and 10 Hz, which point toward the center of
the model. This conductor is interpreted as a clay
cap. Between the depths of 400 – 700 m from the
surface, there is a significantly resistive zone under
Mizugama crater. In another word, the thickness of
the clay cap is significantly reduced as 200m,
compared with the surroundings.
In the deep structure, the 3-D final model
consists of the two parallel conductive blocks (C1
and C2) in a 100 Ω.m homogeneous media where
western conductive block is slightly deeper than
the eastern one. This is also supported by the twodimensional inversion results from multiple
profiles. The resistive gap between deep two
conductive blocks between C1 and C2 is important
feature because it is located just beneath ellipseshaped clay cap. The loss of high conductivity in
this zone implies that the conductive clay cannot
exist as the temperature is significantly higher than
200oC.
Figure 4. The section located in the middle of the
final model.
32
5. Discussion
It has been believed that hydrothermal
system plays an important role under KusatsuShirane volcano associated with volcano activity
[Hirabayashi, 1999, Ohba et al., 2002, Nakano et al.,
2003, Kumagai et al., 2003, Yamazaki et al., 1992].
Some evidences such as hydrothermal surface
manifestation and clay mineral ejected from eruption
were observed in this volcano.
Figure 4 shows resistivity structure, which
is cut from the 3D model corresponding to the
profile located at the center of the model in west-east
direction where the thinner clay mineral takes place.
Interpretation of a 500 m thickness disk-shaped
conductor (C0) located in the center of the model as
a clay mineral is supported by drillhole data provided
by Kurasawa, [1993]. He has reported that The
smectite rich zone was detected below the 1500m
a.s.l and chlorite zone is detected beneath the
smectite zone. Mapping of the low resistive zone as
clay cap (C0 and C1) provides an information of
2000 C isotherms as the bottom of the conductor.
Therefore, high temperature zone should exist in
resistive zone beneath the clay cap. The location and
the size of C0 clay cap coincide with the existence of
the low density material inferred from low gravity
anomaly [Makino et al., 2004]. A resistive block
with size 1 km x 200 m x 200m, capped with the thin
C0 conductor is found at the east of Mizugama crater
where LP resonator is located. Nakano et al. [2003]
pointed out that the LP resonator can be a
hydrothermal reservoir hosting fluids and gases in
the horizontal cracks. In our model, the LP resonator
is just the top part of the geothermal system, capped
by the impermeable clay. The gravity analyses in
association with the resistivity distribution of
regional profiling showed that the western conductor
is in the basement, but the eastern one is above the
basement [Nurhasan et al., 2006]. In this profile 4,
we have re-plotted the gravity basement overlaid on
the resistivity structure. Geologically, the eastern
conductor implies alteration zone in PliocenePleistocene formation while the western conductor
implies alteration zone Miocene formation. This can
explain the different thickness of these conductors
where western conductor is slightly deeper that
eastern conductor.
The temporal magnetization study has the
equivalent dipole location in the resistive zone 900m
from the surface under Mizugama crater [Yamazaki
et al., 1992]. The thermal demagnetization can be
caused by heating process of the volcano where high
temperature (the temperature does not have to reach
the Currie temperature) is considered. They have
found that source of demagnetization is located east
of Mizugama crater at the depth of about 900m from
the surface which corresponds to the Currie
temperature of 5500 C if it is totally demagnetized.
The equivalent dipole locations is in the resistive
zone below the clay cap where higher temperature
than 200oC is expected. Thus our isotherm of
200oC as the bottom of the conductor is consistent
with the geotherm inferred from demagnetization
[Yamazaki et al., 1992].
The western deep conductor (C2) in this
area can be interpreted either as fluids or clay
minerals. There is no helpful information for the
implications of the west conductor such as logging
information. One of the possible interpretations is
the existence of the hot saline fluid which has an
important role in earthquake generation as detected
near this conductor. The existence of the saline
fluid in the porous media can be a candidate to
decrease the bulk resistivity of the rocks. However,
both deep conductors have comparable depth
which means that the interpretation of them should
be not much different. Moreover the existence of
the seismicity is distributed along the gap between
these conductors indicating that not only west
conductor contribute to the earthquake generation
but also another one. Although many papers point
out the relationship between earthquake
distribution and resistivity distribution [Ogawa et
al., 2001; Tank et al., 2003; Kasaya et al., 2002].
Ogawa et al. [2001] pointed out that the seismic
activities have a strong correlation to low
resistivity zone as a sequence of the trapped free
water that discharges from deeper level. Kasaya et
al. [2002] have observed the deep conductor at Mt.
Ontake region and the coincidence to the cutoff
depth of the seismicity. They concluded that the
trapped free water in the brittle-ductile transition
zone is the cause of the earthquake generation.
Such interpretation may also be applicable to the
western deep conductor and the clustering of the
earthquake near the eastern edge of the western
conductor. As we seen in the 3-D final model, both
deep conductors are widely spreading in southnorth direction and hence the more possible
interpretation is clay mineral for west deep
conductor rather than fluids.
6. Conclusion
In summary, we have thus successfully
modeled the three-dimensional resistivity structure
using 3D inversion where distortion-free response
functions such as phase tensors and induction
vectors were used for fitting the data. Moreover,
we investigated the underlying geothermal
structure which was only qualitatively known. The
key of the interpretation was the smectite, which is
electrically conductive
and hydrologically
impermeable. Also underlying thermal structure
was inferred using the bottom of the conductor as a
proxy for 200oC isotherm as the smectite breaks
down above the temperature.
33
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35
MAKALAH 2 : SUBMIT
Journal) , 2010
TO Earth and Planetary Sciences Journal (Int.
INVERSTIGATIO OF SUMATRAN FAULT DERIVED FROM
MAGNETOTELLURIC MODELLING
Nurhasan1, Y Ogawa2, F. Kimata3, D. Sutarno1, D Sugiyanto4
3 RESEARCH CENTER FOR SEISMOLOGY AND VOLCANOLOGY Nagoya University, Japan
4 Physics Department, Syiah Kuala University, Indonesia
Abstracts
Two lines coast to coast broadband MT measurements were carried out in Aceh, Sumatra
Island, Indonesia crossing the Sumatra fault. Using five components of electric and
magnetic sensors, the time series data was recorded in the night time with 12 hours interval
in average at 12 sites. Dimensionality analyses were done by using phase tensor and
induction vector to see the 3D structure of the Sumatra Island. Interpretation of the 3D
resistivity structure was made using 3D MT inversion provided by Weerachai’s code as
well as 2D MT inversion. Based on these results, Sumatra fault is clearly detected by
characterized by contrast resistivity just beneath the fault.
1.
Introduction
Sumatra Fault Zone which is located in Sumatra
Island, Indonesia is an active fault as a result of
strike-slip component of Indo-Australian oblique
convergence. With the length of 1900 Km, Sumatra
fault was divided into 20 segments starting from the
southernmost which has small slip rate and
increasing to the north end of Sumatra Island. A
giant earthquake of Mw=9 stroked the Sumatra
Island following by large tsunami which had wave
magnitude up to 4 -5 m and amplitude of 2 m. The
hypocenter of this event was detected in the south of
Sumatra located at subduction interplate. Seismically,
this megathrust event generated aftershock
distributed not only along the trench of subduction
interface but also along Sumatra Fault Zone
especially in the northern part of Sumatra Fault Zone.
Several multidisciplinary studies have been involved
to investigate implication the giant earthquake to the
region around the hypocenter and Sumatra Fault
Zone. Through research collaboration among
Nagoya University, Tokyo Institute of Technology,
Bandung Institute of Technology and Syiah Kuala
University, We were carried out Magnetotelluric
survey at 12 sites crossing the Sumatra fault and
Seulimeum fault using MTU-5 system provided by
Titech-Japan. The main goal of this research is to
delineate structure of Sumatra and Seulimeum
faults in form of resistivity distribution and their
correlation to the earthquake generation and
deformation process.
2.
Geological Setting
36
3.
Figure 2. Example of observed data which is
representation data from west of the Sumatran
Fault (a) and east of Sumatran Fault (b).
MT Measurements and Processing
MT broad band coast to coast
measurements were conducted in two lines with the
27 total sites. The first line was done in the late of
October and November 2008 crossing the Sumatra
fault and Seulimeum fault through 65 Km of the
length. We used the geophysical Phoenix
Equipments (MTU-5A) provided by Titech-Japan
through research collaboration to record two
components of horizontal electric field, two
components of the horizontal magnetic field and
component of the vertical magnetic field. The time
series data was recorded in the night time with 12
hours interval in average. Data processing and
editing were done using SSMT 2000 embedded in
Phoenix software.
The sample of magnetotelluric data
represented in apparent resistivity and phase are
shown in figure 2. It is clear to see the significant
difference between data obtained from the west part
of Sumatra fault and data from east part of Sumatra
fault. Data from the west of Sumatra fault are
characterized relatively by high apparent resistivity
while data from the east indicated by low apparent
resistivity. This discrepancy is also shown in
representation of induction vector and phase tensor
as shown in figure 3.
4.
Data Representation
Figure 2 shows some representative MT data in
frequency range between 320 Hz to 0.1 Hz.
Relative big error bar are occurred in low
frequency for all data. Limitation of the time length
of recording data may be one of cause of this poor
data. In general, the data can be divided by 2 types
based on the region where data recorded. The data
recorded at the west part of Sumatra fault
characterized by the high resistivity, while in the
east part is characterized by low resistivity. This
indicates that in shallow part, resistivity structure
should be high resistive in west and low resistive in
the east. We have also analyzed the data plotted in
term of induction vector and phase tensor to see
lateral resistivity distribution as shown in figure 3.
The variation of resistivity laterally distribution is
clearly detected by induction vector and phase
tensor. At the frequency of 320 Hz shape of ellipse
phase tensors are distributed randomly indicating
that shallow structure to be 3D structure. For
lower frequencies corresponding to deeper
structure, it is clearly the existence of the 2D
structure representing form the direction of
induction vector and shape of phase tensor.
A-12
B-16
Banda Aceh
A-1
Su
m
at
ra
Fa
ult
Meulaboh
B-1
Figure 3. Observed Phase Tensor and Induction
vector of the Line A in different frequencies
Figure 1. MT sites plotted in the topographic map
including Sumatra and Seulimeum Faults
5.
2D Modeling
As a usual procedure in MT 2D modeling,
it is importance to determine strike direction before
inversion. In this paper, strike direction was
determined based on direction of the fault system
that is clearly detected by induction vector and
phase tensor diagram. Strike direction for the
profile 1 is determined in 45 degree from the north
37
to east as shown in figure 4. This direction of the
fault was also confirmed by geological studies .
Figure 5 shows the final 2D inversion result using
Ogawa and Uchida’s code calculated from apparent
resistivity and phase for TM mode only. The use of
TM mode only calculation is based on the region of
the site location which is distributed in the north end
of Sumatra fault surrounding by ocean. In this case,
TM mode is the reliable mode because of the
insensitivity to the boundary between sea and land .
Homogeneous model of 100 ohm with the 0.3 Ωm.
sea water resistivity included as fix parameter was
used as initial model of inversion. Figure 5 (b) and
(c) indicates the pseudosection of apparent resistivity
and phase obtained form the final model. RMS was
reach in 0.89 With the 20 iteration.
interpreted. In this test, we tested the big conductor
(C1) by replacing it to high resistor (1000 ohm.m)
in some different depth. The result shown that
change of resistivity in this conductor C1 affect
strongly the responses. It means that this conductor
C1 is important feature.
6.
3D Inversion
The region of the study is located at the north end
of Sumatra Island which is fully three dimensional
structure. To overcome the effect of 2D structure
caused by the ocean, 3D inversion using
Weerachai’s code was performed to analyze the
resistivity structure. The 3D model is designed into
100 x 100 x 50 Km in x ,y and z direction with the
100 ohm homogenous model as initial model. This
model area was divided into 20 x 20 x 30 bolck
using same grid in z and y direction. Vertical grids
were constructed logarithmically with 50 m as the
first grid at the surface. In this inversion, the ocean
was modeled as fix parameter with the value of 0.3
ohm.m. The smallest rms was reached at the value
of 3 in 10 iterations.
7. Interpretation and discussion
Figure 4. Rose diagram in 4 decade frequencies
obtained using Groom Bailey Decomposition
technique
Sensitivity Test
Sensitivity test was done to detect whether the
importance features is real from structure or just
artifact structure. This is very important to make sure
that final model is strongly related to the data. If the
result (feature) is not correspond to the data, it means
that the feature is fake (not important) to be
Sumatra Fault is one of the srike-slip fault type
where located at the subduction zone. Differ from
many faults in the word like San Adreass Fault
which is located in one segment along the land,
Sumatra fault is segmented into 20 segments
(Natawidjaja, 2000). Study of geoelectrical
resistivity at fault zone has been discussion in
many papers. Focus of study in the fault zone is not
only how to interpret the resistivity distribution in
the region of fault zone but also it can explain the
mechanism of fault zone process. Spatial resistivity
distribution and presence of the fluid is an
important role in interpretation of the fault
structure. San Andreas Fault which is a sample of
srike-slip fault has several segments in different
mechanism (Usswoth..). Most of the discussions
about the srike-slip fault have shown that the low
resistivity interpreted as fluid zone has strongly
correlated to the seismicity distribution.
Figure 5 shows the final model from 2D inversion
which is look like to be an interesting structure
correlated to the structure in fault zone. Based on
the final model, we divided the resistivity
distribution into shallow and deep structures for
interpretation. The shallow part with depth up to 3
km, resistivity structure can be seen as three
vertical blocks where high resistivity in the west
and east of the profile and low resistivity in the
middle of the profile. Geologically, western part of
38
the Sumatra Fault is a lower cretaceous – upper
Jurasic rocks which electrically has high resistivity
(R1). While Low resistivity in the west of fault
indicated the existence of volcanic rock or volcanic
sediment, Holocene- Pleistocene which was
confirmed exactly by geological studies . There is an
evident that in the east of MT profiling an active
volcano. The sharp boundary between C1 and R1 is
interpreted as strike-slip Sumatran Fault which is a
site location in this area is a boundary fault zone.
This sharp boundary is a typical structure that can
occurred in the srike-slip fault which the dip-slip
angle around 90 degree. This model of srike-slip
fault characterized by sharp boundary has been
performed by 2D modeling ( Unswooth et al., 2003).
The sharp boundary of resistivity block which is
characteristic of strike-slip fault is also detected in
line B. Slightly differ from line A, shallow structure
from line B is more complex. This complexity was
detected well by geological structure. West of the
profile is covered by Holocene-Pleistocene rock.
Middle of the profile is lower Cretaceous-Upper
Jurasic rocks which is higher resistivity nad the east
of the profile is characterized by volcanic rocks and
Pliocene-Eocene rocks.
Interpretation of deep structure is not easy from the
MT study only. Based on the final models, it can be
seen that line A and line B have the similar
resistivity structure which is a vertical conductors
exist in the middle of the profile. Many paper
explained that such conductor located at the depth
below 20 Km form the surface was interpreted as
melting zone (Tank et al., 2003). Since Sumatra
Fault is laid above the intersection subduction plate,
this malting fluid can be one of the candidates for
these vertical conductors. The existence of conductor
C 2 in line A is interpreted as lower crust shear zone
8.
Conclusion
We have successfully imaged the structure of
Sumatra and Seulimeum faults from MT data.
Resistivity structure shows that the fault zone is
characterized by contrast resistivity. By
comparing with the GPS data, it is shown that
conductive part located beneath the fault is
correlated to the depth of locked zone in GPS
studies.
9.
References
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1
MAKALAH 3 : SUBMIT TO Indonesian Physics Journal (Nasional Journal) ,
2010
Dimensionality Analysis of Resistivity Structure of Volcanic Zone from
Magnetotelluric Data
Nurhasan1 , D. Sutarno1, Y. Ogawa2,3
2 Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo, Japan
Abstract
In many cases, three-dimensional resistivity structures are often approximated by twodimensional models without checking the dimensionality of the structure prior to perform
modeling. However, such approximation can be misleading if the structure is purely 3-D
where electromagnetic fields can not be separated into TE and TM modes. Then, a
dimensionality analysis is important in order to get the general feature of the structure in
particular in 3-D structure as expected in volcanic area. There are many methods to analyze
dimensionality such as Groom-Bailey decompositions, which assume that the regional
structure is two-dimensional, and Bahr’s method. Here, we examine the dimensionality
mainly by the phase tensor, which does not assume regional two-dimensional structure at all.
The parameter “beta” is also used as an index for the three-dimensionality of the structure. On
the other hand, the parameter “alpha” is the directional parameter. We also map the phase
tensor diagrams (tan-1(22) as a function of the coordinate angle) and the induction vectors. In
this paper, we have also examined the effect of regional three-dimensional structure to the 2D model. The synthetic and real Magnetotelluric data obtained from volcanic zone were used
in this study.
1. Introduction
Three-dimensional resistivity structures are often approximated by two-dimensional models.
However, such approximation can be misleading if the structure is purely 3-D where
electromagnetic fields can not be separated into TE and TM modes. However, a
dimensionality analysis is important in order to get the general feature of the structure in
particular in 3-D structure. Dimensionality analyses were applied using distortion parameters
(e.g. skew, phase sensitive skew, phase different) for checking dimensionality of the data
(Ledo et. al., 1998 ; 2002). The limitation of these methods is that these parameters are still
affected by the existence of near surface heterogeneity although these are rotationally
invariant. In Groom-Bailey decompositions (Groom et. al., 1989), which assume that the
regional structure is two-dimensional. In this paper, we examined dimensionality of the data
using phase tensor and induction vector analyses. Unlike the conventional polar diagram, the
phase tensor is not affected by three-dimensional shallow structure or galvanic distortion
(Caldwell et al., 2004; Bibby et al., 2005). Parameter “alpha” and “beta” as part of the phase
tensor are used in this study for checking dimensionality. The induction vector is applied to
check the lateral variation.
1
2
2. Methods
2.1. Phase tensor
In this method, we adopted the phase tensor method proposed by Caldwell et al (2004), which
is not affected by galvanic distortion for three-dimensional regional structures. The observed
(distorted) complex impedance tensor can be separated into a real part (X) and an imaginer
part (Y) as follows.
Z  X  iY
Similarly, the regional (undistorted) complex impedance tensor can be separated into a real
part (XR) and an imaginer part (YR) as follows.
Z R  X R  iY R
The magnetotelluric phase tensor is defined as the ratio between the real part and the imaginer
part of the impedance tensor. For observed (distorted) impedance, the phase tensor can be
expressed as
  X 1Y
(1)
In term of the real and imaginer components of impedance tensor, the phase tensor can
be expressed as
  11

 21
12 
1  X 22Y11  X 12Y21


 22  det X   X 11Y21  X 21Y11
X 22Y12  X 12Y22 
X 11Y22  X 21Y12 
where
det  X   X 11 X 22  X 11 X 12
In the plotting of the phase tensor, we calculated the arctangent of the YY-component
of the phase tensor as a function of the coordinate angles (X direction of the rotated frame) by
with 3 degree steps. This plotting is different from those originally defined by Caldwell et al.
(2004). Over a one-dimensional isotropic earth, the phase tensor appears a circle due to
orientation independence of electric and magnetic fields. In a simple of 2-D case where the
model consists of two vertically different resistivity regions (vertical contact model), the
phase tensor will have the appearance of either circle or ellipse oriented in the direction of E
field, depending on the distance from the boundary. The site located on the resistive side near
boundary, phase tensor will be elliptic where the major axis is oriented parallel to the
structure. On the other hand, the site located on the conductive side, major axis of the ellipse
is perpendicular to the contact.
By using the singular value decomposition approach, the phase tensor can be separate to some
matrices as follow:

  R T     max
 0
0 
R    
 min 
(2)
2
3
where
    21 
    21 
1
1
 ;   tan 1  12

  tan 1  12
2
2
  11   22 
 11   22 
 min   12   32    12   32   22 
12

 max   12   32

12
12

  12   32   22

12
The andrepresent the strike direction and three-dimensionality, respectively.
2.2 Induction vector
Besides impedance transfer function, another transfer function called “magnetic transfer
function (Induction vector)” is important for describing lateral variation of resistivity. Since
the magnetic field is free from galvanic distortions, the induction vectors are also free from
distortions. Mathematically, the induction vector (T) is expressed as a ratio of vertical (z) to
horizontal magnetic (Hx and Hy) fields.
H z  Tzx H x  Tzy H y
(3)
The induction vector as defined as (-Tzx, -Tzy) using Parkinson’s convention, reflects
the lateral resistivity anomaly. Graphically the induction vector is defined as the normal unit
vector of the magnetic field by projecting it to the ground. The vector will point to the
conductive side.
3. Application to MT data
3.1. Phase Tensor and Induction Vector
We applied these methods to the real MT data obtained from volcanic region, i.e.
Kusastu Shirane volcano, Japan and Papandayan volcano, Indonesia. Measured phase tensor
plotted together with induction vector (solid line) for Kusatsu Shirane MT data are shown in
Figure 1 for three different frequencies ( 100Hz, 10Hz and 1Hz), representative for shallow,
intermediate (around 500 m) and deep ( > 1 km) penetration depths, respectively.
(a) f=100 Hz
(b) f=10 Hz
Longitude
138.5300
138.5350
Longitude
0
138.540
0
138.5250
138.545
36.6500
36.6500
36.6460
36.6460
Latitude
Latitude
138.5250
36.6420
138.5350
138.5400
138.5450
36.6420
0.2
0.2
900
36.6380
138.5300
0
0
90
200
400
0
36.638
600
Meter
0
200
400
600
Meter
(c) f=1 Hz
3
4
Longitude
138.525 0
138.530 0
138.5350
138.5400
138.5450
0
Latitude
36.650
36.6460
36.6420
0.2
900
36.6380
0
200
400
600
Meter
Figure 1. Measured phase tensor (blue color) and induction vector (red line).
Small blue cross denote distribution of seismicity.
3.2 Parameter beta
Figure 2 shows the “beta” distribution at the summit area in five different frequencies,
i.e., 10 kHz, 1 kHz, and 10 Hz. Dot symbols represent AMT sites (red color) and MT sites
(blue color). At high frequencies (10 kHz, 1000 Hz and 100 Hz), contour area is limited, as
compared with low frequencies (10Hz and 1Hz), because the sites at the north western corner
have no data over 320Hz..
(a) f = 10 kHz
(b) f = 1 kHz
(c) f = 10 Hz
4
5
Figure 2. Distribution of parameter beta for 5 different frequencies
3.3 Parameter alpha
We can check the directional properties of the structure using “alpha”, which is similar to the
strike direction in two dimensional structures.
(a) f = 10 kHz
(b) f = 1 kHz
( c ) f = 10 Hz
( e ) f = 1 Hz
Figure 3. Distribution of parameter alpha in 5 different frequencies
4. Discussion
5
6
By analyzing direction of the major and minor axes of the ellipses, we can predict the
boundary of the resistivity anomaly. The circle-shaped phase tensors as shown at sites located
in the middle of the volcano (Figure 1), indicate that the sites are located in the center of
anomaly far away enough from the boundary. On the other hand, the elliptic phase tensors as
shown at site located eastern part of the volcano, mean the eastern and western boundary of
the conductive anomaly. Based on this explanation, we can depict the elliptic conductivity
anomaly beneath the Mizugama crater (shown by blue dash line in Figure 1.b).
In the inductive vector analysis, at high frequency (100 Hz), directions of inductive
vectors strongly vary with locations, because of the effect of topography or effect of nearly
conductivity anomaly such as vents or hydrothermal manifestations. At the frequency 10 Hz,
the real induction vectors point consistently to the Mizugama crater with magnitude range of
0.02 to 0.20. Although some induction vectors are not consistent, it can be suggested that the
conductive anomaly is located beneath the Mizugama crater.
To confirm the ability of the phase tensor and induction vector in checking
dimensionality, we also examined 3D MT inversion using Siripunvaraporn’s code
(Siripunvaraporn et al., 2005). Based on this result, we have found that resistivity structure of
Kusatsu Shirane volcano can be divided by two parts. The three-dimensional structure has
been found at the shallow part and the 2-D structure has been found in the deeper part. The
phase tensor and induction vector analyses as explained before are consistently to the 3D
inversion results.
Based on the parameter alpha and beta, in general, we can classify the whole area into
two, depending on the value of beta; one with large beta corresponding to 3-D structure and
the other with small beta corresponding to 1-D or 2-D structure. In Figure 2, large beta values
(   2 0 ) are distributed dominantly at high frequencies (10 kHz and 1000 Hz). It means that
in shallow depth (- 500 m from the surface) is characterized by 3-d structure. On the other
hand, deep structures corresponding to the low frequencies (10 Hz) are dominated by small
beta (   2 0 ). This means that the three-dimensionality of the deep structure is weak and the
deep structures are approximately two dimensional. According to Figure 3, it is clear that 3-D
structure is seen at high frequencies (10kHz and 1000Hz ) that are characterized by the
inconsistency of the distribution of alpha. Parameter alpha itself cannot be used to represent
three-dimensionality. However, the distribution of alpha for many sites or frequencies can
give us information of dimensionality by checking their spatial and frequency consistency. At
low frequencies (10Hz and 1Hz), alpha shows consistency around 0 degree that is an
indication of 2-D structure with orientation of strike in the north-south direction.
5. Conclusion
In conclusion, we have successfully analyzed dimensionality using free distortion parameters
(phase tensor and induction vector) applied to MT data of volcanic zone, Kusatu Shirane
volcano. The three-dimensional resistivity structure consisting of conductive zone surrounded
by resistive part is clearly detected by phase tensor and induction vector. Moreover, the
existence of three-dimensional structure at shallow part and 2-D structure at deep part are also
confirmed from parameters alpha and beta analyses. A amazing result has found that there is a
good agreement between 3-D MT inversion result and analyses of these free distortion
parameters.
6. References
6
7
Bahr, K., Geological noise in magnetotelluric data : a classification of distortion types. Phys.
Earth Planet. Inter., 66, 24-38, 1991.
Bibby, H.M., T.G. Caldwell, and C. Brown, Determinable and non-determinable parameters
of galvanic distortion in magnetorllurics, Geophys. J. Int., 163, 915 – 930, 2005
Cagniard, L., Basic theory of the magnetotelluric method of geophysical prospecting.
Geophysics, 18, p.605, 1953
Caldwell, T.G., H.M. Bibby, and C. Brown, The magnetotelluric phase tensor, Geophys. J.
Int., 158, 457 – 469, 2004
Groom, R. W. and R.C. Bailey, Decomposition of magnetotelluric impedance tensor in the
presence of local three-dimensional galvanic distortion, J. Geophys. Res., 94, 1913–
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Ledo, J., P. Queralt, and J. Pous, Effect of galvanic distortion on magnetotelluric data over
three-dimensional regional structure, Geophys, J. Int., 132, 295 - 301, 1998.
Ledo, J., P. Queralt, A. Marti, A.G. Jones, Two-dimensional interpretation of threedimensional magnetotelluric data: an example of limitation and resolution, Geophys, J.
Int., 150, 127-139, 2002.
Mackie, R.L., Madden, T.R. and Wannamaker, P.E., Three-dimensional magnetotelluric
modeling using finite difference equations – Theory and comparisons to integral
equation solutions: Geophysics, 58, 215-226, 1993.
Muller A, and V. Haak, 3-D modeling of the deep electrical conductivity of Merapi volcano
(Central Java): integrating magnetotellurics, induction vectors and the effects of steep
topography, J. Volcano. Geotherm. Res., 138 (3-4): 205-222, 2004.
9.1.1.1.
Nurhasan , Y. Ogawa , N. Ujihara, S.B. Tank , Y. Honkura, S. Onizawa,, T.
Mori , and M. Makino, Two electrical conductors beneath Kusatsu-Shirane volcano,
Japan, imaged by audiomagnetotellurics and their implications for hydrothermal system,
Earth Planets Space, 2006 (in press).
Ogawa, Y., On two-dimensional modeling of magnetotelluric field data, Surv. Geophys., 23
(2-3), 251-273, 2002.
Ogawa, Y., N. Matsushima, H. Oshima, S. Takakura, M. Utsugi, K. Hirano, M. Igarashi, and
T. Doi, A resistivity cross-section of Usu volcano, Hokkaido, Japan, by
audiomagnetotellurics soundings, Earth Planets Space, 50, 339-346, 1998.
Shi, X., H. Utada, J. Wang, W. Siripunvaraporn, Three-dimensional magnetotelluric forward
modeling using vector finite method combined with divergence correction based on the
magnetic fields (VFEH++),
Siripunvaraporn W, Egbert G, Lenbury Y, Uyeshima M. Three-dimensional magnetotelluric
inversion: data-space method. Phys Earth Planet In May 2005;150(1-3):3-14.
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