Observation of short-term variations in the clay minerals ratio after the 2015 Chile great earthquake (8.3Mw) using Landsat 8 OLI data.

In this paper, we explore the potential use of available free Landsat sensor data to investigate the short-term variations (STV) in the clay mineral ratio (CMR) following the 2015 Chile great moment magnitude earthquake ( 8.3 M w) . The present investigation was carried out in the absence of ground observation data. Landsat 8 Operational Land Imager (OLI)-based multi-temporal imageries of before, after and non-earthquakes were used to derive the above parameter by applying the band ratio approach of bands 6 and 7, where the before and after imageries were compared with non-seismic event images as well as for validation. For the temporal automatic lineament data extraction and final lineament mapping, band 8 (panchromatic) was used by applying the LINE algorithm technique of PCI Geomatica, and ArcGIS 10.5 software, respectively. All these derived products finally interact with the regional geology, fault line and lineament systems. The results reveal that CMR can easily identify the STV at temporal scales before and after the earthquake, while both are normal during non-earthquake time. However, this variation was observed in all three buffer zones (i.e., 50, 100 and 150 km buffer) and highly pronounced especially in the fault adjoining areas. Therefore, we found this research to be effective and could be used as an alternative method for future earthquake studies. [ABSTRACT FROM AUTHOR]