Forty years spatio-temporal seismicity distribution and the evidences of the pore pressure impact on triggering earthquakes at the northern part of Lake Nasser, Aswan, Egypt

Abstract

This study has examined the spatial and temporal distribution of seismicity recorded by Aswan seismic local network distributed around the northern part of the Lake Nasser in operation continuously for 40 years (1982–2021). This investigation shows that most of the seismicity is clustered on the Kalabsha fault and its follow up small segments. The seismicity also clustered in the Khor El-Raml area and in the junction of Seiyal fault with Kurkur faults to the North of the Kalabsha fault. The direction of the spatial distribution of the earthquakes in this study shows N–S direction. The temporal major unit is set as one year and the minor unit is set as one day. This study reveals that the accumulation and release of the energy are probably alternated between these active zones. The seismic quiescence has been detected in the Khor El-Raml and in the junction of Seiyal and Kurkur faults since 2007, also the seismic quiescence has been detected in both eastern and western parts of Kalabsha fault since 2015. Therefor, it can be expected a remarkable seismic activity in the near future in one of these active areas. The evidences of the impact of the water infiltration from the lake in triggering earthquakes have been detected in the Abu Dirwa fault, Khor El-Raml area, in the junction of Seiyal and Kurkur faults and in the Spillway fault area. In this study, also the relationship between the earthquakes and the groundwater level of the four piezometer wells in the Seiyal and Spillway fault areas have been examined. Unfortunately, we have not got a clear relation between the groundwater level and the seismicity due to the low seismicity in the Seiyal and Spillway areas during the short operation period of these wells.