Investigation of Spatio-temporal Satellite Thermal IR Anomalies Associated with the Awaran Earthquake (Sep 24, 2013; M 7.7), Pakistan

摘要

The reliable forecast of imminent future earthquakes is still questionable due to uncertainties regarding the complex phenomena of earthquake occurrence and the hierarchical nature of the lithosphere. However, numerous retrospective studies suggest the implications of earthquake-accompanying processes within the context of earthquake forecasting. In this connection, an attempt is made here to verify the enhancement in thermal IR emissions associated with the extraordinary major (M 7.7) and shallow (depth approximate to 15 km) Awaran earthquake (Sep 24, 2013). The satellite thermal imagery record is analyzed to identify the possible effect of pre- and post-seismic changes around the epicentral region (latitude 25-29 degrees N; longitude 63-67 degrees E) for a suitable selected time window (July 27, 2013 to Nov 16, 2013). The pre-earthquake satellite imagery records reveal a very clear and distinct thermal anomaly developed within the earthquake preparation zone almost 6-10 days earlier, while the analysis of post-earthquake imagery record shows a decreasing trend of thermal anomaly as a function of time. The daily land surface temperature (LST) shows an anomalous rise of 7-9 degrees C on Sep 18, 2013, almost 6 days prior to the event occurrence, which is further authenticated by the statistical criterion (with a confidence interval of 95%. Furthermore, the comparative and percentile analysis of daily and 5-year-averaged LST also exhibits abnormal increase associated with this particular event. In addition to all above, the present study is also consistent with the earlier findings and suggests a multi-precursory strategy for earthquake forecasting research.