ANALYSIS OF CHANGES IN STATIC STRESS BEFORE THE 2019 AMBON EARTHQUAKE BASED ON COULOMB FAILURE STRESS AND B-VALUE
On September 26, 2019, a large Mw 6.5 earthquake significantly impacted the cities of Central Maluku, Ambon and West Seram in eastern Indonesia. This earthquake broke an active fault that has not been mapped and exhibits source characteristics with a very complex rupture process. In this study, t...
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| Format: | Theses |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/68954 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | On September 26, 2019, a large Mw 6.5 earthquake significantly impacted the cities
of Central Maluku, Ambon and West Seram in eastern Indonesia. This earthquake
broke an active fault that has not been mapped and exhibits source characteristics
with a very complex rupture process. In this study, the combination of spatial
distribution of Coulomb failure stress (?CFS) and b-value is used to determine the
geodynamic processes that cause earthquakes and serve as an indicator of
increased seismicity. All information on seismic events in the Maluku Region (2-
5°S Latitude and 127-132°E Longitude) from 1980 to 2021 at a depth of 40 km or
less. The correlation between the modeling results ?CFS and the b-value shows
that the source fault segment the 2019 Ambon earthquake was in a high stress state
with a positive ?CFS of 0.1 bar (0.01 MPa) and a low b-value of 0.7 before
earthquake occurs. The source segment of the earthquake was reactivated
by stress changes from a series of large earthquakes around the Manipa and
South Buru faults. The Kawa Shear Zone (KSZ) and Bobot-East Seram show stress
changes on active faults followed by high seismicity. Distribution of positive stress
on the receiver faults suggest that the Ambon City may experience higher seismicity
in the future. |
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