Study of fault plane using the interferometry of aftershocks: case study in the Rigan area of SE Iran

Author(s)

Shirzad, Taghi

• Document type: Journal article
• Source: Geophysical Journal International; v. 217, n. 1, p. 190-205, APR 2019.
• Web of Science Citations: 2

Abstract

Analysis of aftershock events has become an efficient tool to retrieve the empirical Green's function (EGF) between pairs of events by cross-correlation of aftershock event signals. After the Rigan earthquake occurred on 2010 December 20 (M-w 6.5) in southeastern Iran, aftershock events extended along the hidden part of the Kahurak Fault. This study focuses on the investigation and extraction of Rayleigh wave EGFs using the interferometry of aftershock event waveforms. A stacking procedure was then applied to enhance the interevent EGF signal over the period of interest (1 to 3 s). After calculating group/phase velocity dispersion curves, tomography processing was carried out. The tomographic maps indicate three significantly low and two considerably high-velocity anomalies. In the shallow subsurface (<3 km), a low-velocity anomaly coincides with surface ruptures on the Saif Al-Dini small alluvial plain. Other low-velocity anomalies are mainly associated with a barrier formed during the first mainshock. However, a high-velocity anomaly (approximately 15 km(2) in area) explains the asperity leading to the second mainshock occurrence less than a month later, on 2011 January 27 (M-w 6.2). (AU)

• FAPESP's process: 16/20952-4 - Environmental noise tomography in the Pantanal and Paraná basins
• Grantee: Taghi Shirzad Iraj
• Support Opportunities: Scholarships in Brazil - Post-Doctoral