Spatial-temporal analysis of seismicity before the 2012 Varzeghan, Iran, Mw 6.5 earthquake

Mohammad TALEBI; Mehdi ZARE; Rohollah Madahi ZADEH; Aref BALI-LASHAK

doi:https://doi.org/10.3906/yer-1410-13

Makale detayları

Spatial-temporal analysis of seismicity before the 2012 Varzeghan, Iran, Mw 6.5 earthquake

Yazarlar:

Mohammad TALEBI | Mehdi ZARE | Rohollah Madahi ZADEH | Aref BALI-LASHAK

Yayıncı:

TUBITAK

Ana Başlıklar:

Uygulamalı fizik

Dergi:

Turkish Journal of Earth Sciences 2015 Vol.24 Issue 3, pp.289-301

Belge Tipi:

Makale

Yayın Tarihi:

8/2015

Belge Dili:

İngilizce

Document ID (Org No.):

2000731477

Sıklık:

İki Aylık

eISSN:

1303-619X

pISSN:

1300-0985

DOI:

https://doi.org/10.3906/yer-1410-13

Özet:

 

In this work, the spatial and temporal variations of seismicity in northwestern Iran have been evaluated with a special focus on seismic precursors of the 11 August 2012 Mw 6.5 Varzeghan earthquake. The precursors are defined by the z-value test and the generalized fractal dimensions of earthquake epicenters. The investigation applies earthquakes that have occurred since 2006 in a region that includes the main shock and collected by the Iranian Seismological Center. In order to eliminate the effect of explosions in the processing, we removed the explosion from the used catalog by using the normalized ratio analysis of daytime to nighttime events. Having done the preprocessing procedures, we removed the events with magnitudes of less than 2.5. As a result of our analysis, a period of seismic quiescence has been identified, which started about 3 years before the Varzeghan main shock. In a nice coincidence with these results, significant changes have been observed in the generalized fractal dimensions and the related spectra prior to the occurrence of the Varzeghan earthquake. The changes indicate that the seismic activities of the studied area have had increasingly dense clustering in space since about mid-2009, which suggests the regional preparedness for the occurrence of the main quake. Furthermore, the analysis did not exhibit any significant seismic quiescence anomaly at the beginning of 2013.

 

In this work, the spatial and temporal variations of seismicity in northwestern Iran have been evaluated with a special focus on seismic precursors of the 11 August 2012 Mw 6.5 Varzeghan earthquake. The precursors are defined by the z-value test and the generalized fractal dimensions of earthquake epicenters. The investigation applies earthquakes that have occurred since 2006 in a region that includes the main shock and collected by the Iranian Seismological Center. In order to eliminate the effect of explosions in the processing, we removed the explosion from the used catalog by using the normalized ratio analysis of daytime to nighttime events. Having done the preprocessing procedures, we removed the events with magnitudes of less than 2.5. As a result of our analysis, a period of seismic quiescence has been identified, which started about 3 years before the Varzeghan main shock. In a nice coincidence with these results, significant changes have been observed in the generalized fractal dimensions and the related spectra prior to the occurrence of the Varzeghan earthquake. The changes indicate that the seismic activities of the studied area have had increasingly dense clustering in space since about mid-2009, which suggests the regional preparedness for the occurrence of the main quake. Furthermore, the analysis did not exhibit any significant seismic quiescence anomaly at the beginning of 2013.

Makale detayları

Spatial-temporal analysis of seismicity before the 2012 Varzeghan, Iran, Mw 6.5 earthquake

Yazarlar: Mohammad TALEBI | Mehdi ZARE | Rohollah Madahi ZADEH | Aref BALI-LASHAK

Yayıncı: TUBITAK

Ana Başlıklar: Uygulamalı fizik

Dergi: Turkish Journal of Earth Sciences 2015 Vol.24 Issue 3, pp.289-301

Belge Tipi: Makale

Yayın Tarihi: 8/2015

Belge Dili: İngilizce

Document ID (Org No.): 2000731477

Sıklık: İki Aylık

eISSN: 1303-619X

pISSN: 1300-0985

DOI: https://doi.org/10.3906/yer-1410-13

Sayı

Yazarlar:

Mohammad TALEBI | Mehdi ZARE | Rohollah Madahi ZADEH | Aref BALI-LASHAK

Yayıncı:

TUBITAK

Ana Başlıklar:

Uygulamalı fizik

Dergi:

Turkish Journal of Earth Sciences 2015 Vol.24 Issue 3, pp.289-301

Belge Tipi:

Makale

Yayın Tarihi:

8/2015

Belge Dili:

İngilizce

Document ID (Org No.):

2000731477

Sıklık:

İki Aylık

eISSN:

1303-619X

pISSN:

1300-0985

DOI:

https://doi.org/10.3906/yer-1410-13