Off-fault Deformation Associated with Strike-slip Faults

Abstract Habitable buildings can be protected from surface fault rupture by establishing structure “setback zones” similar in purpose to legally mandated zones in California and Utah. But post-earthquake surveys of offset and warped linear cultural features, believed to have been straight prior to the event, demonstrate that potentially damaging inelastic strains or off-fault deformation can extend tens of meters beyond the principal slip zone of strike-slip surface fault ruptures. Setback zones designed to also mitigate off-fault deformation are likely to be prohibitively wide, indicating the need for structural and geotechnical engineering solutions to accommodate the potentially damaging strains within adequate design buffers. This study analyzes nine strike-slip surface fault ruptures between 1906 and 2014 and develops a simplified procedure to quantify off-fault deformation based on earthquake magnitude and distance from the principal slip zone of strike-slip faults.

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Geosynthetics reinforced interposed layer to protect structures on deep foundations against strike-slip fault rupture

Geotextiles and Geomembranes ◽

10.1016/j.geotexmem.2020.11.011 ◽

2020 ◽

Author(s):

Habib Rasouli ◽

Behzad Fatahi

Keyword(s):

Strike Slip ◽

Strike Slip Fault ◽

Deep Foundations ◽

Fault Rupture

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Performance Evaluation of Different SAR-Based Techniques on the 2019 Ridgecrest Sequence

Remote Sensing ◽

10.3390/rs13040685 ◽

2021 ◽

Vol 13 (4) ◽

pp. 685

Author(s):

Marco Polcari ◽

Mimmo Palano ◽

Marco Moro

Keyword(s):

Performance Evaluation ◽

Strike Slip ◽

Seismic Sequence ◽

Fault Rupture ◽

Coseismic Displacement ◽

Surface Rupture ◽

Eastern California Shear Zone ◽

Tectonic Framework ◽

Gnss Network ◽

The One

We evaluated the performances of different SAR-based techniques by analyzing the surface coseismic displacement related to the 2019 Ridgecrest seismic sequence (an Mw 6.4 foreshock on July 4th and an Mw 7.1 mainshock on July 6th) in the tectonic framework of the eastern California shear zone (Southern California, USA). To this end, we compared and validated the retrieved SAR-based coseismic displacement with the one estimated by a dense GNSS network, extensively covering the study area. All the SAR-based techniques constrained the surface fault rupture well; however, in comparison with the GNSS-based coseismic displacement, some significant differences were observed. InSAR data showed better performance than MAI and POT data by factors of about two and three, respectively, therefore confirming that InSAR is the most consolidated technique to map surface coseismic displacements. However, MAI and POT data made it possible to better constrain the azimuth displacement and to retrieve the surface rupture trace. Therefore, for cases of strike-slip earthquakes, all the techniques should be exploited to achieve a full synoptic view of the coseismic displacement field.

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Prediction of Off-Fault Deformation from Experimental Strike-slip Fault Structures using the Convolutional Neural Networks

10.1002/essoar.10507909.1 ◽

2021 ◽

Author(s):

Laainam Chaipornkaew ◽

Hanna Elston ◽

Michele L. Cooke ◽

Tapan Mukerji ◽

Stephan Alan Graham

Keyword(s):

Neural Networks ◽

Convolutional Neural Networks ◽

Strike Slip ◽

Strike Slip Fault ◽

Fault Structures ◽

Fault Deformation

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Oblique convergence causes both thrust and strike-slip ruptures during the 2021 M 7.2 Haiti earthquake

10.31223/x5gg8m ◽

2021 ◽

Author(s):

Ryo Okuwaki ◽

Wenyuan Fan

Keyword(s):

Strike Slip ◽

Fault Rupture ◽

Plate Convergence ◽

Regional Deformation ◽

Blind Thrust ◽

Oblique Convergence ◽

Block Movement ◽

History Of ◽

Tectonic Boundary ◽

Blind Thrust Fault

A devastating magnitude 7.2 earthquake struck Southern Haiti on 14 August 2021. The earthquake caused severe damages and over 2000 casualties. Resolving the earthquake rupture process can provide critical insights into hazard mitigation. Here we use integrated seismological analyses to obtain the rupture history of the 2021 earthquake. We find the earthquake first broke a blind thrust fault and then jumped to a disconnected strike-slip fault. Neither of the fault configurations aligns with the left-lateral tectonic boundary between the Caribbean and North American plates. The complex multi-fault rupture may result from the oblique plate convergence in the region that the initial thrust rupture is due to the boundary-normal compression and the following strike-slip faulting originates from the Gonâve microplate block movement, orienting towards the SW-NE direction. The complex rupture development of the earthquake suggests that the regional deformation is accommodated by a network of segmented faults with diverse faulting conditions.

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