Comparison of Four Moderate-Size Earthquakes in Southern California Using Seismology and InSAR

Mellors, R. J.; Magistrale, Harold; Earle, Paul S.; Cogbill, Allen H.

doi:10.1785/0120020219

Cited by 30 publications

(31 citation statements)

References 43 publications

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“…The minimum threshold for the earthquake search was chosen based on the lowest limit of the coseismic detection capabilities of the DInSAR technique (EARLE and COGBILL 2002;MELLORS et al 2004;LOHMAN and SIMONS 2005;DAWSON and TRE-GONING 2007;DAWSON et al 2008). There are no studies about the sensitivity of DInSAR for detection and characterization of small and moderate sized events in the studied area.…”

Section: Seismicity During the Analyzed Periodmentioning

confidence: 99%

Estimation of Seismic and Aseismic Deformation in Mexicali Valley, Baja California, Mexico, in the 2006–2009 Period, Using Precise Leveling, DInSAR, Geotechnical Instruments Data, and Modeling

Sarychikhina

Glowacka

Robles

et al. 2015

Pure Appl. Geophys.

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Section: Seismicity During the Analyzed Periodmentioning

confidence: 99%

Estimation of Seismic and Aseismic Deformation in Mexicali Valley, Baja California, Mexico, in the 2006–2009 Period, Using Precise Leveling, DInSAR, Geotechnical Instruments Data, and Modeling

Sarychikhina

Glowacka

Robles

et al. 2015

Pure Appl. Geophys.

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“…For large earthquakes, InSAR has proved to be an important tool for source parameter estimation (Bürgmann et al 2000; Dawson & Tregoning 2007; Pritchard & Fielding 2008; Biggs et al 2009a and references therein). This method is independent of the seismic inversion and does not suffer from uncertainties associated with inadequate station coverage and is relatively independent of velocity models (Mellors et al 2004). However, InSAR cannot differentiate between distinct episodes of ground deformation that occur close together in space or between satellite acquisitions.…”

Section: Geodesymentioning

confidence: 99%

Source parameters of the 2008 Bukavu-Cyangugu earthquake estimated from InSAR and teleseismic data

d’Oreye

González

Shuler

et al. 2010

Geophysical Journal International

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S U M M A R YEarthquake source parameter determination is of great importance for hazard assessment, as well as for a variety of scientific studies concerning regional stress and strain release and volcano-tectonic interaction. This is especially true for poorly instrumented, densely populated regions such as encountered in Africa, where even the distribution of seismicity remains poorly documented. In this paper, we combine data from satellite radar interferometry (InSAR) and teleseismic waveforms to determine the source parameters of the M w 5.9 earthquake that occurred on 2008 February 3 near the cities of Bukavu (DR Congo) and Cyangugu (Rwanda). This was the second largest earthquake ever to be recorded in the Kivu basin, a section of the western branch of the East African Rift (EAR). This earthquake is of particular interest due to its shallow depth and proximity to active volcanoes and Lake Kivu, which contains high concentrations of dissolved carbon dioxide and methane. The shallow depth and possible similarity with dyking events recognized in other parts of EAR suggested the potential association of the earthquake with a magmatic intrusion, emphasizing the necessity of accurate source parameter determination. In general, we find that estimates of fault plane geometry, depth and scalar moment are highly consistent between teleseismic and InSAR studies. Centroid-moment-tensor (CMT) solutions locate the earthquake near the southern part of Lake Kivu, while InSAR studies place it under the lake itself. CMT solutions characterize the event as a nearly pure double-couple, normal faulting earthquake occurring on a fault plane striking 350 • and dipping 52 • east, with a rake of -101 • . This is consistent with locally mapped faults, as well as InSAR data, which place the earthquake on a fault striking 355 • and dipping 55 • east, with a rake of -98 • . The depth of the earthquake was constrained by a joint analysis of teleseismic P and SH waves and the CMT data set, showing that the earthquake occurred in the shallow crust, at approximately 8 km depth. Inversions of ENVISAT (Environment Satellite) and ALOS (Advanced Land Observation Satellite) data place the earthquake at 9 km. A comparison of the scalar moment (9.43 ± 0.06 × 10 17 Nm from seismology and 8.99 ± 0.010 × 10 17 Nm from the joint InSAR solution) shows good agreement between the two data sets. Such an agreement is in contrast to the large discrepancies observed (up to an order of magnitude) in other places along the EAR where similar earthquake sequences are associated with magmatic intrusion. From this, we infer that the rupture was brittle and occurred with little aseismic deformation as might be expected from magma injection. Our results provide insights into the style of rifting occurring in the South Kivu Volcanic Province and hence will aid future studies on seismic risk in the context of Lake Kivu and underline the importance of systematic monitoring of the EAR area.

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“…The location of the 1992 Little Skull Mountain earthquake (M s 5.4) in Nevada, reported by the Global Centroid Moment Tensor Project, was off by ∼42 km from that obtained by InSAR (Lohman et al, 2002). Mellors et al (2004) reported that it is difficult to accurately determine the source parameters of moderate-size earthquakes (4 < M < 6) in seismology, especially their epicentral location and focal depth. By systematically comparing earthquake source models derived from InSAR and those from seismic data, Weston et al (2012) found that InSAR provides more accurate location information for shallow events than do seismic catalogs.…”

Section: Introductionmentioning

confidence: 97%

Identifying Active Faults by Improving Earthquake Locations with InSAR Data and Bayesian Estimation: The 2004 Tabuk (Saudi Arabia) Earthquake Sequence

Xu¹,

Dutta²,

Jónsson³

2015

Bulletin of the Seismological Society of America

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A sequence of shallow earthquakes of magnitudes ≤ 5:1 took place in 2004 on the eastern flank of the Red Sea rift, near the city of Tabuk in northwestern Saudi Arabia. The earthquakes could not be well located due to the sparse distribution of seismic stations in the region, making it difficult to associate the activity with one of the many mapped faults in the area and thus to improve the assessment of seismic hazard in the region. We used Interferometric Synthetic Aperture Radar (InSAR) data from the European Space Agency's Envisat and ERS-2 satellites to improve the location and source parameters of the largest event of the sequence (M w 5.1), which occurred on 22 June 2004. The mainshock caused a small but distinct ∼2:7 cm displacement signal in the InSAR data, which reveals where the earthquake took place and shows that seismic reports mislocated it by 3-16 km. With Bayesian estimation, we modeled the InSAR data using a finite-fault model in a homogeneous elastic halfspace and found the mainshock activated a normal fault, roughly 70 km southeast of the city of Tabuk. The southwest-dipping fault has a strike that is roughly parallel to the Red Sea rift, and we estimate the centroid depth of the earthquake to be ∼3:2 km. Projection of the fault model uncertainties to the surface indicates that one of the westdipping normal faults located in the area and oriented parallel to the Red Sea is a likely source for the mainshock. The results demonstrate how InSAR can be used to improve locations of moderate-size earthquakes and thus to identify currently active faults.

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Comparison of Four Moderate-Size Earthquakes in Southern California Using Seismology and InSAR

Cited by 30 publications

References 43 publications

Estimation of Seismic and Aseismic Deformation in Mexicali Valley, Baja California, Mexico, in the 2006–2009 Period, Using Precise Leveling, DInSAR, Geotechnical Instruments Data, and Modeling

Estimation of Seismic and Aseismic Deformation in Mexicali Valley, Baja California, Mexico, in the 2006–2009 Period, Using Precise Leveling, DInSAR, Geotechnical Instruments Data, and Modeling

Source parameters of the 2008 Bukavu-Cyangugu earthquake estimated from InSAR and teleseismic data

Identifying Active Faults by Improving Earthquake Locations with InSAR Data and Bayesian Estimation: The 2004 Tabuk (Saudi Arabia) Earthquake Sequence

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