Changes observed in land surface and air temperature after the Yushu (China) (6.9 M_w) and Kaikoura (New Zealand) (7.8 M_w) earthquakes using Landsat thermal and geophysical datasets.

Land surface temperature (LST) and air temperature changes have been reported in several recent earthquake studies by numerous researchers, with some success and some limitations. The present study focused on this aspect and studied the LST and two geophysical parameters (i.e., 2-m air temperature and surface temperature) changes after the two different magnitude earthquakes that occurred in Yushu of China (6.9 Mw) in 2010 and Kaikoura of New Zealand (7.8 Mw), respectively, in 2016. First, the study observed changes in LST and analyzed the data considering three different time phases, i.e., before the earthquake (BEQ), after the earthquake (AEQ), and non-earthquake (NEQ) periods Landsat satellite thermal datasets. A detailed interpretation was made thereafter considering the earthquake epicenter location based on three buffer zones (i.e., 0–50, 50–100, and 100–150 km buffers). The study finally observed continuous changes in two geophysical parameters targeting a similar time frame and image extension of Landsat datasets. The results of this study observed spatiotemporal variations of LST from Landsat thermal data in both earthquakes from the epicenter to 150 km distance. Moreover, two geophysical parameters, temperature anomalies, are found to be more suitable for detecting the changes that strongly correlate with seismic activity. Thus, this study recommends LST, 2-m air temperature, and surface temperature changing phenomena as the key precursors, along with proposed criteria that could be effectively used for future earthquake research. Research highlights: This research studied the LST changes after the two different magnitude earthquakes. In this study, three different time phases, i.e., before, after, and non-earthquake periods of Landsat satellite thermal datasets, are considered. The study precisely analyzed LST changes based on the three buffer zones (i.e., 0–50, 50–100, and 100–150 km buffers) considering the earthquake epicenter. The study results observed spatiotemporal variations of LST in both earthquakes from the epicenter to the 150 km distance. LST variations and 2-m air temperature show anomalies that strongly correlate with seismic activity. [ABSTRACT FROM AUTHOR]