Relokasi Hypocentre Gempa Bumi Dengan Velest (JHD) dan Estimasi Sesar Daerah Sumatra Selatan

Irwansyah Ramadhani, Bagus Jaya Santosa

Abstract


Gempa bumi merupakan fenomena alam yang tidak terduga kehadirannya. Dalam magnitude yang besar dapat menimbulkan bencana lainnya yaitu tsunami yang menyebabkan kerusakan infrastruktrur dan korban jiwa. Manusia tidak dapat memastikan kapan bencana gempabumi terjadi, tetapi dapat memperkirakan zona yang rawan akan gempabumi, daerah yang berdampak kerusakan besar, dan perkiraan-perkiraan mengenai waktu terjadinya gempa berikutnya. Cara untuk mengetahui hal tersebut dengan menentukan lokasi pusat gempa (hypocentre) sesungguhnya, model dan karakteristik (sesar maupun patahan) bawah permukaan bumi. Velest merupakan metode JHD (Join Hypocentre Determination) dengan menggunakan banyak event gempa yang diinversi
sekaligus (simultan) untuk mendapatkan hypocentre yang sebenarnya. Penentukan model bumi satu dimensi dari velest ini berdasarkan kecepatan gelombang P dan gelombang S. Karakteristik bawah permukaan dilakukan dengan ISOLA yang mampu memberikan gambaran mengenai sesar maupun patahan di suatu daerah. Kedua program tersebut digunakan untuk merelokasi event-event gempa di daerah Sumatra Selatan dan mengetahui karakteristik bumi yang ditentukan melalui momen tensor. Selain dua program tersebut, digunakan algoritma
STFT dan CWT untuk analisis gelombang P. Hasil penelitian ini didapatkan metode JHD mampu merelokasi hypocetre gempa serta didapatkannya model bumi 1 dimensi dan momen tensor untuk 4 event menyatakan
bahwa pola sesar yang terdapat pada daerah laut Sumatera Selatan merupakan dip-slip.


ABSTRACT


Earthquake is an unpredictable natural phenomena in occurance which has harmfull consequences. In high magnitude, it can cause other disaster i.e. tsunami which result in hard demage infrastructure and loss of population.
One can not determine earthquake presence exactly, however can estimate earthquake prone zone, major hard demage zone, and next earthquake presence. They can be estimated through hypocentre determination
and earths model. Velest is an JHD ((Join Hypocentre Determination) based method which applies all events to inverted simultaneously and results true hypocentre of earthquake. In other hand, Velest can determine one dimensional earths model based P and S wave travel time data. Then, earths characteristic can be determined by ISOLA. It is able to provide an imaging of fault in a research area through moment tensor. Both Velest
and ISOLA applies in this research. Arrival time of P wave is analized by STFT and CWT algorithm. Then, Velest applies to earthquake events relocation while ISOLA applies to determine earths characteristic (fault) in
Southern Sumatra. This research note that velest is able to determine true hypocentre of earthquake well and one dimensional earth model of South Sumatra. In other hand, moment tensor of 4 events show geometry of
fault in Souther Sumatra is dip-slip.


Keywords


Earthquake, ISOLA, Velest, Momen Tensor, JHD

Full Text:

PDF

References


D.H. Natawidjaja, and W. Triyoso, J. Earthq. Tsunami, 1, 21-47 (2007).

R. McCaffrey, Annu. Rev. Earth Planet. Sci., 37, 345-366 (2009), doi:10.1146/annurev.earth.031208.100212

K. Sieh, and D.H. Natawidjaja, J. Geophys. Res., 105, 28295- 326 (2000).

P. Bird, Geochem. Geophys. Geosyst, 4, 1-52 (2003).

P. Sarin, and P. Dabas, International Journal of Computer Science and Information Technologies, 7(2),893-895 (2016).

S. Azadi, and A.A. Safavi, S-transform based P-wave and S wave arrival times measurements toward earthquake locating, in Control, Instrumentation and Automation (ICCIA), 2nd International Conference on. IEEE, 241-246 (2011).

R. Simm, and M. Bacon, Seismic amplitude: an interpreter handbook (Cambridge University Press, Cambridge, New York, 2014).

D. Pei, Modeling and inversion of dispersion curves of surface waves in shallow site investigations, ProQuest (2007).

S. Stein, and M. Wysession, An introduction to seismology, earthquakes, and earth structure (Blackwell Pub, Malden, MA, 2003).

H. Grandis, Pengantar Pemodelan Geofisika (HAGI, Jakarta, 2009).

E. Kissling, U. Kradolfer, H. Maurer, Program VELEST user’s guide-Short Introduction, Inst. Geophys. ETH Zurich, 1995.

W. Astuti, et al., Adaptive Short Time Fourier Transform (STFT) Analysis of seismic electric signal (SES): A comparison of Hamming and rectangular window, in Industrial Electronics and Applications (ISIEA), IEEE Symposium on. IEEE, 372-377, 2012.

R.H. Herrera, et al., IEEE Geosci. Remote Sens. Lett., 12, 364368 (2015), doi:10.1109/LGRS.2014.2342033

H.A. Nofal, et al., Near optimum detection of the p-wave arrival using the spectrograms, in Electrical, Electronic and Computer Engineering, ICEEC004. 2004 International Conference on. IEEE, 710-715, 2004.

C.I. Huerta-Lopez, et al., Time-frequency analysis of earthquake records, in 12th World Conference on Earthquake Engineering, Auckland, 2000.




DOI: http://dx.doi.org/10.12962/j24604682.v13i2.2744

Refbacks

  • There are currently no refbacks.


Creative Commons License
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.