TOMOGRAFI SEISMIK ZONA GEMPABUMI YOGYAKARTA 27 MEI 2006 BERDASARKAN KATALOG GEMPABUMI SUSULAN; SEISMIC TOMOGRAPHY OF MEI 27, 2006 YOGYAKARTA EARTHQUAKE ZONE BASED ON AFTERSHOCK CATALOGUE

Diambawa, Atria D, Wiwit Suryanto

2015 | Skripsi | FMIPA

On May 27, 2006 at 05:54 am had happened an earthquake Mw 6.3 in Yogyakarta that caused severe damage. This earthquake was caused by the Opak active fault oriented with northeast-southwest. The fault geometry was debatable, thus it is necessary to know the geometry using modeling tomography. Seismic tomographic inversion had been done to model the subsurface structure in Yogyakarta area based on P-and S-wave velocity anomaly and Vp/Vs ratio. Seismic wave observation arrival time were compared to seismic wave theoritical arrival time using aftershocks data that recorded at 10 stations around fault zone. Hypocenters of earthquake are located 10-15 km to the east of Opak fault at 20 km depths. Based on the result of this seismic tomographic inversion, high Vp/Vs ratio value assosiates with soft-sediment deposits where severe damage occur. The result also shows the pattern of subsurface fault. The primary sign of Opak fault pattern until 5-7 km depths is reverse fault where the hanging wall is in the east side and foot wall is in the west side of Opak fault.

Kata Kunci : N