Editorial Summary: Bam Earthquake of 05:26:26 of 26 December 2003, Ms6.5
M. Ghafory-Ashtiany

The Magnitude Ms = 6.5 earthquake of 26th December 2003 occurred at early morning (05:26:26 local time) along Bam fault with no recorded of any major earthquake, at least, approximately in past 2500 years; and while many residents of the Bam historical city were still sleeping. The traditional mud-brick and clay homes put up little resistance to the violent shaking, and as walls and roofs crumbled and collapsed; more than 100,000 of victims were trapped beneath the rubble and from them around 26,500 lost their lives. Close to 11,000 of the city’s students perished, along with one to five of Bam’s 5,400 teachers. Tens of thousands were left homeless and up to 6,000 children were orphaned. Arg-e-Bam (Bam Citadel), the largest mud-brick complex in the world and other historical buildings were almost totally destroyed. Bam earthquake not only shook the heart and mind of the Iranian, but the world and created on the biggest human solidarity. This earthquake have created a new initiative in Iran’s risk reduction program and consequently provides a unique window of opportunity to raise international awareness of the importance of the effective implementation of a comprehensive earthquake risk reduction program in hazard-prone countries.

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In this study at the first step, the database of two temporary networks of International Institute of Earthquake Engineering and Seismology (IIEES) and Institute of Geophysics of Tehran University (IGTU), which deployed independently after the Ghaen-Birjand earthquake, were merged. Based on the new database, focal mechanisms of some larger aftershocks were obtained and crustal model of eastern Iran [3] modified for the epicentral area of Ghaen-Birjand earthquake and its aftershocks. The Vp/Vs ratio is inferred as 1.85 for the region covered by the temporary seismic networks. After relocation of more than two hundred events, it was cleared that at least three of the largest aftershocks were estimated to be located with a precision corresponding to error ellipsoid axes within 5 to 10 km (Ground Truth level of 5 to 10).

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Focal Depths of Moderate and Large Size Earthquakes in Iran
A. Maggi, K. Priestley, and J. Jackson

Accurate focal depth estimates are essential for the correct interpretation of seismicity data in terms of regional tectonics and earthquake hazard assessment. Published global earthquake catalogues are a common source of focal depth information, but how accurate are they? We compare estimates of focal depths from the Harvard CMT catalogue and the Engdahl et al [8] relocations of the ISC catalogue with those determined by teleseismic waveform inversion methods, and find that the catalogues can be in error by up to 60km.

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Deterministic Seismic Hazard Assessment for North Morocco
F. Vaccari, B. Tadili, A. El Qadi, M. Ramdani, L. Ait Brahim and M. Limouri

The purpose of this work is to evaluate the regional seismic hazard for Morocco, following the deterministic approach proposed by Costa et al [1], based on the computation of complete P-SV and SH synthetic seismograms. The input for the computations is represented by source and structural models. Seismic sources are parameterized using the knowledge about past seismicity and the tectonic regime. The regional structural model we adopted is the one proposed by Cherkaoui [2], modified in its shallower part to account for the effects of the uppermost sedimentary layers. Maps of peak acceleration, velocity, and displace-ments are used for the general representation of the hazard. Accelerations are in good agreement with the values determined by Jimenez et al [3] with the standard probabilistic approach.

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