Finite fault inversion of the September 25, 1999 (Mw = 6.4) Taiwan earthquake: Implications for GPS displacements of Chi-Chi, Taiwan earthquake sequence

The 10 June 2012 (UTC 12:44:17.3; lat. 36.441°N, long. 28.904°E, Mw6.0) earthquake sequence, 60 km to the west of Rodos Island, is studied, in an attempt to shed light to the obscure deformation pattern at the easternmost end of the Hellenic Arc. Moment tensor solutions for the mainshock and the strongest aftershocks revealed the operation of WNW-ESE dextral strike-slip faulting, with slip vector at~N295°E, approximately orthogonal to the GPS velocity vectors. The strike of the activated structure generally aligns with bathymetric linear escarpments observed in the region, bordering the eastern section of the Rodos basin. The best constrained focal depths are in the range 10 to 25 km, with the mainshock at the depth of 24 km.The slip model for the mainshock, obtained through a finite-fault inversion scheme, showed that slip was mainly concentrated in a single patch, with the locus of peak slip (~125 cm) located ~ 4km to the NW of the hypocenter. The sequence which lies in the western continuation of the Fethiye – Burdur sinistral strike-slip zone into theAegean Sea and Rodos basin, is not connected with activation of this zone. Its characteristics comply with the activation of a dextral strike-slip structure, oblique to this zone, which accommodates along – arc NE-SW extension.

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Consecutive ruptures on a complex conjugate fault system during the 2018 Gulf of Alaska earthquake

Scientific Reports ◽

10.1038/s41598-021-85522-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Shinji Yamashita ◽

Yuji Yagi ◽

Ryo Okuwaki ◽

Kousuke Shimizu ◽

Ryoichiro Agata ◽

...

Keyword(s):

Gulf Of Alaska ◽

Source Model ◽

Fault System ◽

Complex Conjugate ◽

Inversion Method ◽

Fault Geometry ◽

Conjugate System ◽

Finite Fault Inversion ◽

Finite Fault ◽

Alaska Earthquake

AbstractWe developed a flexible finite-fault inversion method for teleseismic P waveforms to obtain a detailed rupture process of a complex multiple-fault earthquake. We estimate the distribution of potency-rate density tensors on an assumed model plane to clarify rupture evolution processes, including variations of fault geometry. We applied our method to the 23 January 2018 Gulf of Alaska earthquake by representing slip on a projected horizontal model plane at a depth of 33.6 km to fit the distribution of aftershocks occurring within one week of the mainshock. The obtained source model, which successfully explained the complex teleseismic P waveforms, shows that the 2018 earthquake ruptured a conjugate system of N-S and E-W faults. The spatiotemporal rupture evolution indicates irregular rupture behavior involving a multiple-shock sequence, which is likely associated with discontinuities in the fault geometry that originated from E-W sea-floor fracture zones and N-S plate-bending faults.

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THE 2014 MW 6.9 NORTH AEGEAN TROUGH (NAT) EARTHQUAKE: SEISMOLOGICAL AND GEODETIC EVIDENCE

Bulletin of the Geological Society of Greece ◽

10.12681/bgsg.11877 ◽

2017 ◽

Vol 50 (3) ◽

pp. 1583

Author(s):

V. Saltogianni ◽

M. Gianniou ◽

T. Taymaz ◽

S. Yolsal-Çevikbilen ◽

S. Stiros

Keyword(s):

Broad Band ◽

Strike Slip ◽

Fault Geometry ◽

Coseismic Slip ◽

The North ◽

Finite Fault Inversion ◽

Seismological Data ◽

Finite Fault ◽

Slip History ◽

North Aegean

A strong earthquake (Mw 6.9) on 24 May 2014 ruptured the North Aegean Trough (NAT) in Greece, west of the North Anatolian Fault Zone (NAFZ). In order to provide unbiased constrains of the rupture process and fault geometry of the earthquake, seismological and geodetic data were analyzed independently. First, based on teleseismic long-period P- and SH- waveforms a point-source solution yielded dominantly right-lateral strike-slip faulting mechanism. Furthermore, finite fault inversion of broad-band data revealed the slip history of the earthquake. Second, GPS slip vectors derived from 11 permanent GPS stations uniformly distributed around the meizoseismal area of the earthquake indicated significant horizontal coseismic slip. Inversion of GPS-derived displacements on the basis of Okada model and using the new TOPological INVersion (TOPINV) algorithm permitted to model a vertical strike slip fault, consistent with that derived from seismological data. Obtained results are consistent with the NAT structure and constrain well the fault geometry and the dynamics of the 2014 earthquake. The latter seems to fill a gap in seismicity along the NAT in the last 50 years, but seems not to have a direct relationship with the sequence of recent faulting farther east, along the NAFZ.

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Insights into Seismogenic Deformation during the 2018 Hualien, Taiwan, Earthquake Sequence from InSAR, GPS, and Modeling

Seismological Research Letters ◽

10.1785/0220180228 ◽

2018 ◽

Vol 90 (1) ◽

pp. 78-87 ◽

Cited By ~ 8

Author(s):

Jiun‐Yee Yen ◽

Chih‐Heng Lu ◽

Rebecca J. Dorsey ◽

Hao Kuo‐Chen ◽

Chung‐Pai Chang ◽

...

Keyword(s):

Earthquake Sequence ◽

Taiwan Earthquake

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Efficient Bayesian uncertainty estimation in linear finite fault inversion with positivity constraints by employing a log-normal prior

Geophysical Journal International ◽

10.1093/gji/ggz044 ◽

2019 ◽

Vol 217 (1) ◽

pp. 469-484 ◽

Cited By ~ 5

Author(s):

Roberto Benavente ◽

Jan Dettmer ◽

Phil R Cummins ◽

Malcolm Sambridge

Keyword(s):

Uncertainty Estimation ◽

Finite Fault Inversion ◽

Finite Fault ◽

Log Normal

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Active Faulting in Source Region of 2016–2017 Central Italy Event Sequence

Earthquake Spectra ◽

10.1193/101317eqs204m ◽

2018 ◽

Vol 34 (4) ◽

pp. 1557-1583 ◽

Cited By ~ 11

Author(s):

Fabrizio Galadini ◽

Emanuela Falcucci ◽

Stefano Gori ◽

Paolo Zimmaro ◽

Daniele Cheloni ◽

...

Keyword(s):

Source Region ◽

Central Italy ◽

Active Faults ◽

Earthquake Sequence ◽

Fault System ◽

Fault Plane Solutions ◽

Moment Tensors ◽

Central Italy Earthquake ◽

Finite Fault ◽

Main Shocks

The Central Italy earthquake sequence produced three main shocks: M6.1 24 August, M5.9 26 October, and M6.5 30 October 2016. Additional M5–5.5 events struck this territory on 18 January 2017 in the Campotosto area. Fault plane solutions for the main shocks exhibit normal faulting (characteristic of crustal extension occurring in the inner central Apennines). Significant evidence, including hypocenter locations, strike and dip angles of the moment tensors, inverted finite fault models (using GPS, interferometric aperture radar, and ground motion data), and surface rupture patterns, all point to the earthquakes having been generated on the Mt. Vettore–Mt. Bove fault system (all three main shocks) and on the Amatrice fault, in the northern sector of the Laga Mountains (portion of 24 August event). The earthquake sequence provides examples of both synthetic and antithetic ruptures on a single fault system (30 October event) and rupture between two faults (24 August event). We describe active faults in the region and their segmentation and present understanding of the potential for linkages between segments (or faults) in the generation of large earthquakes.

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Construction of fault geometry by finite-fault inversion of teleseismic data

10.31223/osf.io/92hsw ◽

2020 ◽

Author(s):

Kousuke Shimizu ◽

Yuji Yagi ◽

Ryo Okuwaki ◽

Yukitoshi Fukahata

Keyword(s):

Fault Geometry ◽

Finite Fault Inversion ◽

Teleseismic Data ◽

Finite Fault

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Rupture Kinematics of the 11 January 2021 Mw 6.7 Hovsgol, Mongolia, Earthquake and Implications in the Western Baikal Rift Zone

Seismological Research Letters ◽

10.1785/0220210061 ◽

2021 ◽

Author(s):

Gang Liu ◽

Xuejun Qiao ◽

Pengfei Yu ◽

Yu Zhou ◽

Bin Zhao ◽

...

Keyword(s):

Baikal Rift Zone ◽

Tien Shan ◽

Deformation Pattern ◽

Convergence Region ◽

The North ◽

Finite Fault Inversion ◽

Teleseismic Data ◽

Finite Fault ◽

The Right ◽

Rupture Kinematics

Abstract The Mongolia plateau is the farthest intracontinental region of the India–Eurasia collision and is a transition zone between north–south convergence to the south in the Tien Shan and northwest–southeast extension to the north in the Baikal rift. Mongolia has experienced four M 8 earthquakes since 1905, but due to limited observations, the mechanism of these strong earthquakes and regional tectonics are poorly understood. The 11 January 2021 Mw 6.7 Hovsgol, Mongolia, earthquake is the largest event that has occurred in the Hovsgol graben, which is noted for being the northernmost convergence region of the India–Eurasia collision and the youngest extension region of the Baikal rift. In this article, the coseismic displacements are retrieved by space geodesy for the first time in this region, providing good constraints for the deformation pattern. We use a finite-fault inversion of InSAR and teleseismic data, and a backprojection analysis to reveal the rupture kinematics of this event. The geometry of the Hovsgol fault is determined as east-dipping with a dip of 45°. The rupture process is characterized by a northwestward propagation with a moderate average rupture velocity of ∼2.0 km/s and a complex slip pattern composed of two major slip patches with dimensions of 40 km×20 km. The oblique slip, illustrated by predominate extension and significant dextral striking, confirms the right-lateral-striking faulting in the Hovsgol rift, which indicates that the eastwardly north–south convergence across the southwest segment of the Baikal rift has decreased.

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