Coseismic and Early Postseismic Analysis of Earthquakes Using Static and Kinematic Data (Case Studies of The Flores M7.4 2021, Cianjur M5.6 2022, and Pasaman M6.1 2022 Earthquakes)

Sujanto, Anandiko (2025) Coseismic and Early Postseismic Analysis of Earthquakes Using Static and Kinematic Data (Case Studies of The Flores M7.4 2021, Cianjur M5.6 2022, and Pasaman M6.1 2022 Earthquakes). Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

This research rigorously investigates the coseismic and early postseismic deformation associated with three significant Indonesian earthquakes: the 2021 Flores (M7.4), the 2022 Cianjur (M5.6), and the 2022 Pasaman (M6.1) events. Utilizing both static and kinematic Global Positioning System (GPS) data acquired from InaCORS networks, position changes were carefully analyzed using GipsyX software. Coseismic displacements were precisely estimated, revealing substantial and complex horizontal and vertical deformation for Flores (e.g., station CUMB recorded approximately 0.46 m horizontal and 0.34 m vertical subsidence), predominantly strike-slip motion for Cianjur, and clear right-lateral strike-slip for Pasaman (e.g., station CPSM recorded a coseismic eastward displacement of approximately 0.012 m). Kinematic Precise Point Positioning (KPPP) solutions consistently provided superior temporal resolution, effectively capturing instantaneous coseismic jumps and rapid initial displacements. The Okada (1985) elastic half-space model was employed to predict theoretical coseismic deformation, showing qualitative agreement in displacement patterns with observed KPPP data, particularly for the dominant strike-slip Pasaman event however, it frequently underestimated observed magnitudes for the more geometrically complex Flores and Cianjur ruptures, underscoring the inherent limitations of simplified elastic models. Furthermore, early postseismic afterslip was distinctly observed across all three events, with KPPP data consistently revealing more rapid decay characteristics (e.g., logarithmic τ values ranged from 0.09 days to 1.823 days) compared to static solutions (often extending to tens or hundreds of thousands of days), indicating KPPP's ability to resolve the rapid early postseismic phase. This substantial contribution of early afterslip highlights its crucial role in accommodating residual stress and influencing the overall slip budget of the earthquake cycle, thereby significantly enhancing the understanding of crustal deformation dynamics, fault behavior, and stress redistribution in these seismically active regions of Indonesia.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	afterslip, coseismic, postseismic, earthquake, GPS, GipsyX, Okada model, static data, kinematic data.
Subjects:	G Geography. Anthropology. Recreation > G Geography (General) G Geography. Anthropology. Recreation > G Geography (General) > G109.5 Global Positioning System G Geography. Anthropology. Recreation > GB Physical geography G Geography. Anthropology. Recreation > GB Physical geography > GB651 Subsidences (Earth movements)
Divisions:	Faculty of Civil, Environmental, and Geo Engineering > Geomatics Engineering > 29202-(S1) Undergraduate Theses
Depositing User:	Anandiko Savieros Sujanto
Date Deposited:	25 Jul 2025 02:48
Last Modified:	25 Jul 2025 02:48
URI:	http://repository.its.ac.id/id/eprint/121562

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