Earthquake signatures in the ionosphere detected by GPS measurements

Kurzfassung

The ionospheric response to earthquakes has been reported in the literature since many years. Since the effects are extremely small, sensitive detection techniques have to be applied. Dense networks of GPS receivers, available nowadays, provide a reliable data base for studying earthquake induced signatures in more detail. Using the dense GPS network in North America, relative TEC data from differential phases were analyzed to detect signatures in correlation to selected earthquakes of magnitude > 6. Earthquake related structures were found after the Denali earthquake on 3/11/2002 and during the California earthquake on 22/12/ 2003. It is assumed that these significant structures are associated to acoustic waves excited in the atmosphere by seismic waves. Detection techniques and wave propagation features will be discussed.