LG PHASE EFFICIENCY PROPAGATION AND THE INTENSITY OF GROUND SHAKING IN THE NORTH WESTERN PART OF SYRIA

Mohamad, Randa; Al-Samara, Mohammad; Sandvol, Eric

doi:10.21608/jesaun.2012.113122

LG PHASE EFFICIENCY PROPAGATION AND THE INTENSITY OF GROUND SHAKING IN THE NORTH WESTERN PART OF SYRIA

Document Type : Research Paper

Authors

¹ Syrian National Earthquake Centre, Damascus, SYRIA, phD student.

² Higher Institute of Earthquake studies and research, University of Damascus, SYRIA.

³ Department of Geological Sciences, University of Missouri Colombia, Missouri, USA

10.21608/jesaun.2012.113122

Abstract

The high level of seismicity at the regional seismic sources around Syria and the good distribution of the 57 seismic network stations in Syria and surrounding areas (Turkey, Cyprus, Jordan) allowed a detailed characterization of regional Lg phase propagation and definition of the parts where this phase is clearly seen, well developed and zones of Lg blockage by determining the values of Lg Q0 (Q at 1 Hz) over these paths using the standard two-station method. Since the Lg phase for distances larger than 150 km carries substantial energy for large events [1], and the differences in efficiency of propagation influences the intensity of ground shaking [2]. Thus, in this study, were correlated the good paths of lg phase with the intensity contours of the 1822, 1872 historical large determined, earthquake located at the north western part of Syria [3] and the pick ground acceleration recorded at Syrian strong motion stations of the recent event (22 June 1997) with magnitude 4.9 located in the same region of historical events [4],[5]. It is found that the trend of north east direction extended for the historical intensity contours and the high pick ground acceleration observed for the recent event (22 June 1997) are taking the same trend as Lg efficient propagation in that Area.

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