Spatial-temporal variation of the land surface temperature field and present-day tectonic activity

Abstract

This study attempts to acquire information on tectonic activity in western China from land surface temperature ( LST) field data. On the basis of the established relationship between heat and strain, we analyzed the LST distribution in western China using the satellite data product MODIS/Terra. Our results show that: 1. There are departures from annual changes of LST in some areas, and that these changes are associated with the activity of some active tectonic zones. 2. When annual-change background values caused by climate factors are removed, the long-period component ( LST LOW) of temperature residual (Δ T) of the LST is able to serve as an indicator for tectonic activity. We have found that a major earthquake can produce different effects on the LST fields of surrounding areas. These effects are characterized by both rises and drops in temperature. For example, there was a noteworthy temperature decline associated with the Sumatran M9 earthquake of 2004 in the Bayan Har-Songpan block of central Tibetan Plateau. 3. On the other hand, the LST field of a single area may respond differently to major shocks occurring in different areas in the regions surrounding China. For instance, the Kunlun M 8.1 event made the LST on the Longmen Mountains fault zone increase, whereas the Zaisan Lake M 7.9 quake of 2003, and the Sumatran M 9 event of 2004, caused decreases in the same area’s LST. 4. The variations of land surface temperature ( LST) over time are different in different tectonic areas. These phenomena may provide clues for the study of tectonic deformation processes. On the basis of these phenomena, we use a combination of temperature data obtained at varied depths, regional seismicity and strain results obtained with GPS measurements, to test the information related to tectonic activity derived from variations of the LST field, and discuss its implications to the creation of models of regional tectonic deformation.