Seismicity patterns associated with the September 10th, 2008 Qeshm earthquake, South Iran

Sorbi, Mohammad Reza; Nilfouroushan, Faramarz; Ahmad, Zaini

doi:10.1007/s00531-012-0771-6

Cited by 13 publications

(4 citation statements)

References 45 publications

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“…A b-value greater than 1.0 is related to the areas of crustal heterogeneity and low applied stress [61][62][63]. However, the b-value lower than 1.0 indicates high differential stress [61][62][63] and volumes with crustal homogeneity [64][65][66].…”

Section: Frequency-magnitude Relationshipmentioning

confidence: 99%

The b-Value Analysis of Aftershocks 170 Days After the 23 October 2011 Van Earthquake (M w, 7.1) of the Lake Van Basin, Eastern Anatolia: A New Perspective on the Seismic Radiation and Deformation Characteristics

Toker¹

2017

Earthquakes - Tectonics, Hazard and Risk Mitigation

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In this study, we analyzed the seismic radiation and deformation characteristics of the 2011 Van earthquake during aftershock events with the support of estimated dynamic parameters (seismic b-value and radiation efficiency, ηR), 3D crustal cross sections of aftershock hypocenters, and deformation styles of Lake Van basin. The resulted variation in the b-value exhibits two dramatic changes in the b-value: one (b > 1) during the first 100 days of the mainshock and the other (b < 1) in the last 70 days of the mainshock. The constant b (b = 1) indicates a seismically active time interval and transitional variation in the b-value from high to low. The estimated b-value (b >1) reveals that the aftershock sequence comprised a large number of the small and same-sized events of the Van mainshock due to the extreme material heterogeneity within the rupture zone. This indicates a general decrease in shear stress and increasing complexity in the focal area. The small value (ηR < < 1) of ηR implies that the amount of energy mechanically dissipated during the Van rupture process is large. This reveals that the microscopic breakdown process dominates the rupture dynamics and the whole Lake Van basin. The 3D crustal images of hypocenters suggest that the Van event originated in a strongly heterogeneous fractured setting with the aseismic sedimentary section of Lake Van. The high b-value combined with the low radiation efficiency (ηR) shows a strongly faulted-fractured sediment-rock formation filled with gas-fluid. This suggests that the seismic energy is intermittently released in the discrete form of aftershock events which is controlled by nonuniform and highly heterogeneous stresses, associated with the deformation style of Lake Van. The frequent redistribution of flickering stresses and nonlinear deformations in the rupture area increase the b-value and decrease the radiation efficiency.

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Section: Frequency-magnitude Relationshipmentioning

confidence: 99%

The b-Value Analysis of Aftershocks 170 Days After the 23 October 2011 Van Earthquake (M w, 7.1) of the Lake Van Basin, Eastern Anatolia: A New Perspective on the Seismic Radiation and Deformation Characteristics

Toker¹

2017

Earthquakes - Tectonics, Hazard and Risk Mitigation

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“…Statistical Z test, used in several studies [15,[29][30][31], is a proper approach for studying the changes of seismicity-rate and seismic quiescence or acceleration. For example, Z-mapping approach measures the di erence between the seismicity-rate, within moving time windows, and background rate by standard deviate Z.…”

Section: Introductionmentioning

confidence: 99%

Analyses of seismicity parameters of the August 11th, 2012, Ahar-Varzaghan earthquakes in north-western Iran

Ommi

Zafarani

2016

Scientia Iranica

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North-western Iran (Azerbaijan province), one of the most seismic regions of the country, has experienced many seismic events during its long history. The recent dual earthquake with M w = 6:4 and M w = 6:3 struck the Ahar-Varzaghan area in Azerbaijan province in 2012.8.11 and caused a lot of fatalities. In this paper, the varieties of several seismic parameters, such as the b-value of the Gutenberg-Richter relation and standard deviation, Z, have been investigated to explore the temporal and spatial changes of seismicity patterns. Calculating and comparing these data before and after the occurrence of earthquake demonstrate some information about anomaly preceding main shocks. Temporal variations of b-value show a clear decrease before the 2012 Ahar-Varzaghan dual earthquakes. Considering the spatial changes in the b-values, it is possible to recognize a zone with abnormal low b-values around the epicenter of these events. The variation of the b and Z-values around the epicenter shows preparedness of the region before the occurrence of the main shock of Ahar-Varzaghan earthquake.

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“…The Z value is one of the additional techniques for detecting the precursory seismic quiescence that occurs before strong-to-major earthquakes. For examples, the M w -5.8 Coyote lake earthquake, USA and the M w -6.2 Morgan Hill earthquake ( Bachman, 2001), the 2008 M w -6.4 SW-Achaia, Western Greece (Chouliaras, 2009), the 2003 M w -7.6 Colima earthquake (Rudolf-Navarro, Diosdado, and Angulo-Brown, 2010), the 2003 M w -8.3 Tokachi-Oki, Japan ( Katsumata, 2011), the M w -6.4 Turkey earthquake (Öztürk and Bayrak, 2011), and the 2006 M w -6.1 Silakhour, Iran (Sorbi, Nilfouroushan, and Zamani, 2012)in Figure 1.7.…”

mentioning

confidence: 99%

“…(a) Topographic map of the study area with significant faults and earthquakes (b) Map of the spatial distribution of Z statistic before the 6.1 M w earthquake in 2008 in South Iran.The white star indicates the epicenter of the 2008 Qeshm main shock. The red colour indicates a positive Z value, which corresponds to a drop in seismicity rate, whereas the blue colour indicates an increase in seismicity rate (Sorbi et al, 2012).…”

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confidence: 99%

Investigation of statistical seismology in Thailand-Laos-Myanmar borders

Neanudorn

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The purpose of this research is to understand more about the statistical seismology of the Thailand-Laos-Myanmar border�in order to monitor earthquake activity and locate potentially dangerous area. The seismicity data was collected�from the Thailand Meteorological Department. Following that, the catalog's homogeneity and completeness were improved. The first step is to identify the earthquake activity by using the adaptive frequency-magnitude distribution. The results are that Nan province, Thailand, and south Luang Prabang, Laos are the highest activity areas which can generate a maximum magnitude of 5.1 ML, 5.6 ML, 6.3 ML, and 6.7 ML in 5, 10, 30, 50 years. The return period with the ML of 4.0, 5.0, 6.0, and 7.0 was 1, 5, 20, and 75 years. The probability of the occurrence of the earthquake with the ML of 4.0, 5.0, 6.0, and 7.0 was 100%, 100%, 70-100%, and 20-60%, respectively. Then, identify the prospective area using three methods: b value, Z value , and RTL algorithm. After performing iterative tests on three methods with the appropriate parameterd, reasonable estimates of the anomalous precursors. Overlaying maps of those three methodologies makes it possible to identify prospective places for a coming major earthquake. The Thailand-Myanmar border region, Nan province, Thailand, and southwest of Luang Prabang, Laos are the most risk areas for the earthquake in the future.

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Seismicity patterns associated with the September 10th, 2008 Qeshm earthquake, South Iran

Cited by 13 publications

References 45 publications

The b-Value Analysis of Aftershocks 170 Days After the 23 October 2011 Van Earthquake (M w, 7.1) of the Lake Van Basin, Eastern Anatolia: A New Perspective on the Seismic Radiation and Deformation Characteristics

The b-Value Analysis of Aftershocks 170 Days After the 23 October 2011 Van Earthquake (M w, 7.1) of the Lake Van Basin, Eastern Anatolia: A New Perspective on the Seismic Radiation and Deformation Characteristics

Analyses of seismicity parameters of the August 11th, 2012, Ahar-Varzaghan earthquakes in north-western Iran

Investigation of statistical seismology in Thailand-Laos-Myanmar borders

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