Historical and Modern Seismicity of the Semipalatinsk Test Site

Abstract

According to the current maps of general seismic zoning of the Republic of Kazakhstan (2006), the territory of the Semipalatinsk Test Site (STS) is considered an aseismic region. However, recent investigations and an analysis of archived data have shown that the Test Site territory and its vicinity have experienced and still experience tectonic and induced earthquakes. The maximum magnitude of recorded earthquakes is 5–5.9. An analysis of global seismological bulletins and data on historical seismicity from literature sources is performed to solve the problem of seismicity in the STS region. Historic analog seismograms of earthquakes have been collected since 1925; the earthquake parameters are estimated more precisely. Modern instrumental seismic data of the Kazakhstan monitoring network since 1994 are processed, as is the data of temporary networks of seismic stations operating on the territory of the test site in 2005–2010 in the region of the Sary-Uzen, Balapan, and Degelen test sites. These works resulted in the creation of a common earthquake catalogue for the STS territory and its vicinity from 1783 up to the present. Macroseismic data of the felt earthquakes have been collected; strong motion records have been analyzed. Deep faults dividing Earth’s crust blocks have been marked out. Tectonic elements are located by decoding the Landsat space images and using materials of geologic and topographic surveys. The calculations show that the STS territory can experience events with intensity 6 based on the MSK-64 scale.