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:: Volume 5, Issue 2 (6-2014) ::
GEJ 2014, 5(2): 9-18 Back to browse issues page
Coseimic Gravity Change Estimation due to Ahar-Varzagan Dual Earthquakes
A. Rastbood
Abstract:   (4223 Views)
Any knowledge of a fault motions and its effects such as gravity field changes is the main reason of this research. After large earthquakes some deformations occur in the Earth’s crust. It’s important to note that as a result of an earthquake whole of the Earth and not just it’s surface is deformed. Since displacement field causes mass redistribution so gravity field and geoid height change after an earthquake. In this research, the general method of different gravity field component changes due to an earthquake in a fault with an arbitrary geometry and slip is investigated. For this purpose Green function method for blind fault in an elastic half space is used and analytical closed functions for coseismic gravity changes due to a plane dislocation is introduced. Combination of obtained results of modeling and observed gravity change we can use it as a tool for geometry determination of a dislocation or geoid height change in the area of earthquake occurrence. Simulation results shows that a large earthquake can change the geoid height upto one meter. The 2012/8/11, Mw = 6.5 and Mw = 6.3 dual earthquakes of Varzagan and Ahar in East Azerbaijan Province of NW Iran is examined and gravity changes due to these earthquakes is estimated. Computation results show that gravity field changes due to an earthquake is more than the instrumental precision. It’s important to note that this model could be implemented for any other fault in the study area with an arbitrary geometry properties and gravity field changes could be estimated for any point. For the first event Mw = 6.5 of Ahar-Varzagan dual earthquakes total gravity changes is in the range of -10.929 microgal to 10.257 microgal. Also for the second one Mw = 6.3 this range is from -43.977 microgal to 16.545 microgal. Obtained results show that gravity field changes for a strike slip fault is less than dip slip or tensile faults.
Keywords: Coseismic change, dislocation, gravity acceleration, gravity potential, geoid, Ahar-Varzaghan dual earthquakes
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Type of Study: Research | Subject: Geo&Hydro
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A. Rastbood. Coseimic Gravity Change Estimation due to Ahar-Varzagan Dual Earthquakes. GEJ 2014; 5 (2) :9-18
URL: http://gej.issge.ir/article-1-64-en.html

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Volume 5, Issue 2 (6-2014) Back to browse issues page
نشریه علمی مهندسی نقشه برداری و اطلاعات مکانی Geospatial Engineering Journal