•  
  •  
 

Corresponding Author

Mariam Ramadan Awad

Authors ORCID

0009-0008-1311-5946

Document Type

Original Study

Subject Areas

Geology

Keywords

Epidemic-type aftershock sequence; Dependent earthquakes removal; Northeastern Egypt; Spatiotemporal earthquake distribution

Abstract

Earthquakes have the largest damaging effects among natural disasters on a global scale. Efforts for reducing their effects have taken place for a long time. The prediction of earthquakes was the main target, however the studies conducted were not successful. As a replacement, seismic hazard assessments were adopted to predict the levels of ground motion for the possible future large earthquakes. This approach is probabilistic in nature that rely on the quality of earthquake catalog. The probabilistic model adopted is built on the assumption that the events in the earthquake catalog are random Poisson distribution, assuming that events are independent of each other. Hence, dependent events should be removed from the catalog. This algorithm is called seismic declustering. It’s a step towards conducting a reliable seismic hazard analysis for the region. For this reason, the epidemic-type aftershock sequence (ETAS) model is tested to investigate its efficiency to remove dependent events from the catalog of northeastern Egypt. ETAS code is an R package for fitting the space-time ETAS model to an earthquake catalog, especially large datasets, using the stochastic declustering approach. For this purpose, an earthquake catalog for the rectangular geographical region 26º-33º N and 30-36 E representing the northeastern part of Egypt, and period between 1985 and 2022 was extracted and processed. Applying the whole catalog data to the code results in missing the main shocks of some seismic zones of the study area. A better solution to this problem was achieved by subdividing the data in time for periods close to these main shocks. However, the Aqaba event that took place on 22nd November 1995 failed to appear as background activity. The reason for this comes from the foreshocks that preceded the main shock. For this reason, the event is added manually to the catalog.

Download

Share

COinS