1-D seismic velocity model and hypocenter relocation using double difference method around West Papua region

Author(s):  
Agung Sabtaji ◽  
Andri Dian Nugraha
2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
I. Bernal ◽  
H. Tavera

In this study, we present a velocity model for the area of the 2007 Pisco-Peru earthquake ( Mw = 8.0 ) obtained using a double-difference tomography algorithm that considers aftershocks acquired for 6 months. The studied area is particularly interesting because it lies on the northern edge of the Nazca Ridge, in which the subduction of a large bathymetric structure is the origin of geomorphological features of the central coast of Peru. Relocated seismicity is used to infer the geometry of the subduction slab on the northern flank of the Nazca Ridge. The results prove that the geometry is continuous but convex because of the subduction of the ridge, thereby explaining the high uplift rates observed in this area. Our inferred distribution of seismicity agrees with both the coseismic and postseismic slip distributions.


2021 ◽  
Vol 873 (1) ◽  
pp. 012070
Author(s):  
M Ramdhan ◽  
Priyobudi ◽  
A Mursityanto ◽  
K H Palgunadi ◽  
Daryono

Abstract The 2020 Sumbawa earthquake of moderate magnitude (M 5.3) produced very significant aftershocks. Based on the computation of Utsu’s method, those aftershocks would be ended after the 20th day. Those earthquakes along 20 days were relocated using double-difference method. The relocation results show the southwest-northeast orientation and getting deeper into the northwest direction. Those two directions show the strike and the dip from the fault plane of the earthquake which was consistent with the focal mechanism released by the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG). Those results showed the majority of earthquakes occurred at a depth of shallower than 20 km. Those earthquake depths were fit with the previous study showing the crustal thickness beneath Sumbawa Island that was about 28 km. We also found that those earthquakes occurred at splay faults propagating to decollement structure. This study is beneficial for earthquake disaster mitigation especially in updating active faults on Sumbawa Island.


2018 ◽  
Vol 89 (2A) ◽  
pp. 603-612 ◽  
Author(s):  
Andri D. Nugraha ◽  
Hasbi A. Shiddiqi ◽  
Sri Widiyantoro ◽  
Clifford H. Thurber ◽  
Jeremy D. Pesicek ◽  
...  

2021 ◽  
Vol 873 (1) ◽  
pp. 012099
Author(s):  
Wahyu Hidayat ◽  
David P. Sahara ◽  
Sri Widiyantoro ◽  
I Putu Raditya Ambara Putra ◽  
Nabiel H. Shihab ◽  
...  

Abstract Hypocenter relocation is one of the keys to success in the analysis of seismicity induction in underground mines. Overburden thickness, topography, geological complexity, and mining activities can result in newly induced seismicity that can endanger the safety of underground mine workers. The relatively narrow underground mine area requires the most accurate hypocenter location information possible. The double-difference algorithm approach is one of the keys to overcoming this problem. The double-difference method is a relative location method that tries to minimize the residuals between the observed and calculated travel time differences for pairs of microseismic events at each station, by adjusting the differences between all pairs of events at each station repeatedly. In this study, we utilized microseismic measurement data in the deepest underground mine in Indonesia. A total of 1783 seismic events were successfully relocated. The relocation results show the rock mass stress which is illustrated by the distribution of events around the cave, especially the abutment area and underground mining tunnels.


Author(s):  
Andri Dian Nugraha ◽  
Shindy Rosalia ◽  
Sri Widiyantoro ◽  
Pepen Supendi ◽  
Samsul Wiyono ◽  
...  

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