paper by Inmaculada Dura-Gomez and Pradeep Talwani,

Pure Appl. Geophys., DOI: 10.1007/s00024-009-0012-5

ABSTRACT

Based on the analysis of seismogeological background, the Three Gorges Reservoir area is divided into 31 units according to different combined conditions of induced earthquake, together with 8 influencing factors, to give the prediction on probability and magnitude of RIS by adopting statistical prediction model, fuzzy mathematics and gray system model as well as artificial neural network model respectively. The results show as follows: in 31 units, the slight differences exist in results among three predictive methods, especially distinction between mathematics statistics models and artificial neural network model, which is also quite coincident with past macroscopical analogical prediction. The results are not only in accord with the past researchers’ basically, but also confirm with each other better: (1)from dam site to Miaohe segment, due to its geologic background, superficial fracture dislocation type of RIS may be triggered mainly, and the maximum (ultimate) magnitude will not exceed 3.0; (2) it is possible to trigger 4.5-6.0 earthquake in three places, including limestone area of southern Badong, near reservoir segment of Longchuanhe limestone area and far from reservoir segment of Gaoqiao Fracture limestone area; (3) it’s quite likely that the certain activity of Gaoqiao Fracture trigger tectonic reservoir induced earthquake.

by Hassoup AWAD and Grzegorz KWIATEK 

Abstract 

We obtained seismic moment tensor solutions of ten events from the June 1987 earthquake swarm, which occurred along the Kalabsha fault zone in the northern part of the Lake Aswan area in Egypt. In addition, the composite fault plane solution of this sequence was also calculated. The waveform data were ob-tained from the Aswan seismological network, which consists of 13 field stations with short period seismometers GS-13. The June 1987 swarm was a sequence of microearthquakes (M ≤ 3.4), shallow (0-10 km) events forming two successive bursts, which took place on June 17 and 19.
The moment tensor solutions indicate that the focal mechanisms of events from this swarm sequence are expressed by right-lateral strike slip faults. They represent also an effective east-west compressional stress field acting in the area. Geological and geophysical data demonstrate that the Kalabsha fault zone is a right-lateral strike slip fault that consists of several fault segments trending in the east-west direction, perpendicular to the axis of the main course of the Lake As-wan. Thus, the focal mechanisms of the 1987 events are consistent with the local tectonics of the area.

Full text: http://agp.igf.edu.pl/files/53/3/Awad-Kwiatek.pdf