The 2010 Mw 6.5 Rigan, Iran, Earthquake Aftershock Sequence

Rezapour, Mehdi; Mohsenpur, Amir

doi:10.1785/0120120288

Cited by 14 publications

(7 citation statements)

References 17 publications

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“…Because both of these measurements yield measurements near the fault, we are able to resolve near‐surface fault slip. The collocation of locally recorded aftershocks with inferred slip suggests that the observed surface displacement signals result from the coseismic rupture [ Rezapour and Mohsenpur , ] rather than being due to triggered aseismic slip. The earthquake likely does not rupture the surface, with a minimum slip depth of ~1.5 km (Figure c).…”

Section: Surface Deformation Sourcesmentioning

confidence: 99%

Active accommodation of plate convergence in Southern Iran: Earthquake locations, triggered aseismic slip, and regional strain rates

2013

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We present a catalog of interferometric synthetic aperture radar (InSAR) constraints on deformation that occurred during earthquake sequences in southern Iran between 1992 and 2011, and explore the implications on the accommodation of large‐scale continental convergence between Saudi Arabia and Eurasia within the Zagros Mountains. The Zagros Mountains, a salt‐laden fold‐and‐thrust belt involving ~10 km of sedimentary rocks overlying Precambrian basement rocks, have formed as a result of ongoing continental collision since 10–20 Ma that is currently occurring at a rate of ~3 cm/yr. We first demonstrate that there is a biased misfit in earthquake locations in global catalogs that likely results from neglect of 3‐D velocity structure. Previous work involving two M ~ 6 earthquakes with well‐recorded aftershocks has shown that the deformation observed with InSAR may represent triggered slip on faults much shallower than the primary earthquake, which likely occurred within the basement rocks (>10 km depth). We explore the hypothesis that most of the deformation observed with InSAR spanning earthquake sequences is also due to shallow, triggered slip above a deeper earthquake, effectively doubling the moment release for each event. We quantify the effects that this extra moment release would have on the discrepancy between seismically and geodetically constrained moment rates in the region, finding that even with the extra triggered fault slip, significant aseismic deformation during the interseismic period is necessary to fully explain the convergence between Eurasia and Saudi Arabia.

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Section: Surface Deformation Sourcesmentioning

confidence: 99%

Active accommodation of plate convergence in Southern Iran: Earthquake locations, triggered aseismic slip, and regional strain rates

2013

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“…The Ridgecrest sequence represents an example of cross-fault ruptures where two earthquakes occur on faults oriented~90°to each other. Previous documented examples of cross-fault ruptures include the 1987 Superstition Hills, California, earthquake sequence (Hudnut et al, 1989;Larsen et al, 1992), the 1992 Big Bear and Landers, California, earthquakes (Jones & Hough, 1995), the 2010 M w 7.1 Darfield, New Zealand, earthquake (Barnhart et al, 2011;Elliott et al, 2012), the 2010-2011 Rigan, Iran, earthquake sequence (Rezapour & Mohsenpur, 2013;Walker et al, 2013), and the 2012 M w 8.6 Sumatra earthquake (Meng et al, 2012;Wei et al, 2013). Apparent from this list, cross-fault ruptures are relatively common in Southern California, though the phenomenon is rare globally to the best of our observational capabilities.…”

Section: Introductionmentioning

confidence: 99%

The July 2019 Ridgecrest, California, Earthquake Sequence: Kinematics of Slip and Stressing in Cross‐Fault Ruptures

Barnhart

Hayes

Gold

2019

Geophysical Research Letters

125

128

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The July 2019 Ridgecrest, California, earthquake sequence produced cross‐fault ruptures from a Mw6.4 left‐lateral foreshock and a Mw7.1 right‐lateral mainshock. We use interferometric synthetic aperture radar and satellite optical imagery to characterize the surface displacements and subsurface fault slip characteristics of the sequence. We document ~46 km of surface rupture and peak slip values of ~5 m associated with the Mw7.1 and evidence that the two ruptures crossed each other. We additionally document evidence of triggered creep along 20–25 km of the central Garlock fault. Static stress change analysis shows that the foreshock sequence systematically promoted slip at the Mw7.1 hypocenter. Moreover, we find static stress changes promoted slip on the Garlock fault only in locations where we document surface creep, strongly indicating that the Garlock fault is sensitive to static stress changes. A potential rupture of the Garlock fault where slip was promoted could produce a Mw6.7–7.0 earthquake.

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“…This type of complex geometrical structure fault is widespread. Previous records of conjugate faults include the 1992 Big Bear and Landers earthquakes in California 4 , 2010 Darfield Mw7.1 earthquake in New Zealand 5 , 6 , 2010–2011 seismic sequence in Rigan 7 , 8 , and 2018 Gulf of Alaska Mw7.9 earthquake 9 , 10 . The orthogonality of the two main faults and the effects of their seismic interaction have attracted extensive attention.…”

Section: Introductionmentioning

confidence: 99%

Coseismic fault-slip distribution of the 2019 Ridgecrest Mw6.4 and Mw7.1 earthquakes

Gao

Duan

Zhang

et al. 2021

Sci Rep

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The 2019 Ridgecrest, California seismic sequence, including an Mw6.4 foreshock and Mw7.1 mainshock, represent the largest regional seismic events within the past 20 years. To obtain accurate coseismic fault-slip distribution, we used precise positioning data of small earthquakes from January 2019 to October 2020 to determine the dip parameters of the eight fault geometry, and used the Interferometric Synthetic Aperture Radar (InSAR) data processed by Xu et al. (Seismol Res Lett 91(4):1979–1985, 2020) at UCSD to constrain inversion of the fault-slip distribution of both earthquakes. The results showed that all faults were sinistral strike-slips with minor dip-slip components, exception for dextral strike-slip fault F2. Fault-slip mainly occurred at depths of 0–12 km, with a maximum slip of 3.0 m. The F1 fault contained two slip peaks located at 2 km of fault S4 and 6 km of fault S5 depth, the latter being located directly above the Mw7.1hypocenter. Two slip peaks with maximum slip of 1.5 m located 8 and 20 km from the SW endpoint of the F2 fault were also identified, and the latter corresponds to the Mw6.4 earthquake. We also analyzed the influence of different inversion parameters on the fault slip distribution, and found that the slip momentum smoothing condition was more suitable for the inversion of the earthquakes slip distribution than the stress-drop smoothing condition.

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The 2010 Mw 6.5 Rigan, Iran, Earthquake Aftershock Sequence

Cited by 14 publications

References 17 publications

Active accommodation of plate convergence in Southern Iran: Earthquake locations, triggered aseismic slip, and regional strain rates

Active accommodation of plate convergence in Southern Iran: Earthquake locations, triggered aseismic slip, and regional strain rates

The July 2019 Ridgecrest, California, Earthquake Sequence: Kinematics of Slip and Stressing in Cross‐Fault Ruptures

Coseismic fault-slip distribution of the 2019 Ridgecrest Mw6.4 and Mw7.1 earthquakes

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