Assessment of Coulomb Stress Changes Associated with the 1995 Aigion Earthquake in the Gulf of Corinth (Greece)

Mitsakaki, C.; Sakellariou, Michael; Tsinas, Demitris; Marinou, Aggeliki

doi:10.1007/978-3-540-38596-7_21

Cited by 2 publications

(1 citation statement)

References 16 publications

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“…The seismic fault rupture results in accumulation of the forces that cause a lasting alteration in the stress field in a region nearby the earthquake location, and it is termed as static stress change. Such a change is found to be influenced by different parameters, namely, earthquake location, rupture shape, and type of fault motion (Mitsakaki et al, 2006). One way to quantify this change is through the Coulomb failure function (ΔCFF) analysis, which is influenced by variations in both shear stress (Δτs) and normal stress (Δσn).…”

Section: Coulomb Stress Change Analysismentioning

confidence: 99%

Unravelling seismogenesis and characterizing the unique features of two significant felt earthquakes (M > 4.0) of 2020 in the southwestern parts of the Delhi region

Prajapati,

Pandey,

Bhattacharjee

et al. 2024

Front. Earth Sci.

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Two significant earthquakes (M4.6 and 4.2) occurred close to a NE–SW-trending lineament in the southwestern part of the Delhi NCR (National Capital Region) within a short time span of about 5 months in 2020. These events were located to the north of the Alwar district in Rajasthan and generated a significant ground shaking in and around Delhi. In the present study, we tried to understand a causal relationship between the events and a nearby source in the region, geologically demarcated as the lineament. We analyzed the broadband waveform data from 26 seismic stations that recorded the recent events of 03 July 2020 (M4.6) and 17 December 2020 (M4.2). Typically, the epicentral area has been devoid of significant earthquakes since the past six decades; however, a few minor events (M < 4.0) have been recorded till date. Analysis of the earthquake database for two decades (2000–2022) revealed low seismicity (nearly quiescent-like situation) in ∼100 sq km area around the epicentral zone, unlike considerable seismicity along faults/lineaments close to the Delhi region. The full-waveform inversion analyses of the events indicate normal faulting with a minor strike–slip components. The source parameters, viz., source radius, stress drop, and seismic moment, were estimated to be 6 km, 166 bars, and 8.28E+15 Nm, respectively, for the 03 July 2020 event and 4 km, 138 bars, and 2.29E+15 Nm, respectively, for the 17 December 2020 event. The causative source of these events is ascertained based on the stress inversion modeling that indicated a NW–SE tensile stress corroborating well with the NE–SW-trending lineament mapped in the study region. The static Coulomb stress modeling indicated that the event which occurred on 3 July 2020 had advanced the triggering process of the event in the northeast segment of the same source that occurred on 17 December 2020. We further emphasize that the aforementioned lineament probably activated due to the regional tectonics of the study area. The causative source of these events with strike 48°, dip 86°, and rake −60° is found to be in the conformity with the local tectonics and is well-supplemented by a high stress ratio (0.70 ± 0.05) and low friction coefficient (0.5).

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Section: Coulomb Stress Change Analysismentioning

confidence: 99%

Unravelling seismogenesis and characterizing the unique features of two significant felt earthquakes (M > 4.0) of 2020 in the southwestern parts of the Delhi region

Prajapati,

Pandey,

Bhattacharjee

et al. 2024

Front. Earth Sci.

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Seismicity and Fault Interaction in the Gulf of Aqaba

Abdelazim

Gabry

Gobashy

et al. 2023

Pure Appl. Geophys.

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The Gulf of Aqaba is considered one of the most seismotectonically active regions in the Middle East. This study analyzes the seismic activity from 1983 to 2018 to investigate the spatio-temporal distribution of the events in the Gulf’s three basins. The seismic activity is characterized by conventional mainshock–aftershock sequences and swarm activity. Most activity is located in the Aragonese basin, while the Dakar basin shows less seismic activity. The b-value was calculated for the three basins from the declustered catalogue, representing the fingerprint of the transform fault. Within the Aragonese, three significant earthquakes occurred in 1993, 1995, and 2015 with moment magnitude (Mw) of 5.8, 7.2, and 5.2, respectively. An intermediate seismic quiescence preceded the three earthquakes. The quiescence time for the 1995 earthquake began at the tail of the aftershocks of the 1993 mainshock, suggesting that the two earthquakes were not entirely independent. At the tail of the 1995 earthquake aftershocks, the seismic activity spread across the Gulf, increasing in frequency and decreasing in magnitude. A similar pattern was observed for the seismic quiescence preceding the 2015 mainshock. The occurrence of the three significant and proximal earthquakes in the Aragonese region over a 22-year interval, with the described similarities, suggests a link between these earthquakes. Finally, the Coulomb stress transfer shows that the 1993 source fault seems to increase the stress loading on the 1995 left-lateral strike-slip fault, and the latter would also increase the stress transfer on the 2015 left-lateral strike-slip fault.

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Assessment of Coulomb Stress Changes Associated with the 1995 Aigion Earthquake in the Gulf of Corinth (Greece)

Cited by 2 publications

References 16 publications

Unravelling seismogenesis and characterizing the unique features of two significant felt earthquakes (M > 4.0) of 2020 in the southwestern parts of the Delhi region

Unravelling seismogenesis and characterizing the unique features of two significant felt earthquakes (M > 4.0) of 2020 in the southwestern parts of the Delhi region

Seismicity and Fault Interaction in the Gulf of Aqaba

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