Ground motion prediction from nearest seismogenic zones in and around Greater Cairo Area, Egypt

This paper reviews the likely source characteristics, focal source mechanism and fault patterns of the nearest effective seismogenic zones to Greater Cairo Area. Furthermore, <i>M</i><sub>max</sub> and ground accelerations related to the effective seismic events expected in future from those seismogenic zones are well evaluated. For this purpose, the digital waveform of earthquakes than <i>M</i><sub>L</sub>=3 that occurred in and around Greater Cairo Area from 1997 to 2008 which have been recorded by the Egyptian National Seismological Network, are used to study source characterization, focal mechanism and fault pattern of the seismogenic zones around Greater Cairo Area. The ground motions are predicted from seismogenic zones to assess seismic hazard in the northeastern part of Greater Cairo, where three effective seismogenic zones, namely Abou Zabul, southeast Cairo trend and Dahshour area, have the largest effect to the Greater Cairo Area. The <i>M</i><sub>max</sub> was determined, based upon an empirical relationship between the seismic moment and the rupture length of the fault during the earthquake. The estimated <i>M</i><sub>max</sub> expected from Abou Zabul, southeast Cairo trend, Dahshour seismic sources are of <i>M</i><sub>w</sub> magnitudes equal to 5.4, 5.1, and 6.5, respectively. The predominant fundamental frequency and soil amplification characteristics at the area were obtained using boreholes data and in-situ ambient noise measurement

Parameterization of 18th January 2011 earthquake in Dalbadin Region, Southwest Pakistan

An earthquake of magnitude 7.3 Mw occurred on 18th January 2011 in Southwestern Pakistan, Baluchistan province (Dalbadin Region). The area has complex tectonics due to interaction of Indian, Eurasian and Arabian plates. Both thrust and strike slip earthquakes are dominant in this region with minor, localized normal faulting events. This earthquake under consideration (Dalbadin Earthquake) posed constraints in depth and focal parameters due to lack of data for evaluation of parameters from Pakistan, Iran or Afghanistan region. Normal faulting mechanism has been proposed by many researchers for this earthquake. In the present study the earthquake was relocated using the technique of travel time residuals. Relocated coordinates and depth were utilized to calculate the focal mechanism solution with outcome of a dominant strike slip mechanism, which is contrary to normal faulting. Relocated coordinates and resulting mechanism are more reliable than many reporting agencies as evaluation in this study is augmented by data from local seismic monitoring network of Pakistan. The tectonics in the area is governed by active subduction along the Makran Subduction Zone. This particular earthquake has strike slip mechanism due to breaking of subducting oceanic plate. This earthquake is located where oceanic lithosphere is subducting along with relative movements between Lut and Helmand blocks. Magnitude of this event i.e. Mw = 7.3, re evaluated depth and a previous study of mechanism of earthquake in same region (Shafiq et al., 2011) also supports the strike slip movement