In 2014, Anshuman Bhardwaj, Post Doc of Atmospheric Science, went to the Langtang region in the Nepalese Himalaya for a field expedition. Together with his research team, they enjoyed the local hospitality and help during the journey in the mountains. Then, in April 2015, an earthquake hit the region.
– The devastation due to earthquake-triggered landslides was extremely tragic. The reports and pictures of the tragedy inspired us to look into this phenomenon through different viewpoints, says Anshuman Bhardwaj.
– Initially we were interested to observe the changes in the mountains using satellite images. However, we observed some unusual depletion of snow cover during a very short span of time which further prompted us to look into the temperature changes and that is how this research culminated.
Warmer snow cover
Besides the Gorkha earthquake in Nepal, the researchers looked into two other great earthquakes, Illapel earthquake in Chile and the Farkhar earthquake in Afghanistan that occurred during 2015. By analyzing data collected throughout 15 years by the MODerate resolution Imaging Spectrometer (MODIS) on board NASA’s TERRA satellite, the researchers observed that there are both warmer and colder anomalies in all the land cover classes studied; non-snow, lake ice and lakes. However, these anomalies are not consistent. Snow on the other hand, is an exception since snow cover is the only land class where they were observing only warmer anomalies and at all of the three earthquakes. Hence, snow surface temperature has been found to be a consistent reference to increase future predictability of high magnitude earthquakes within a temporary margin of two to three weeks before their occurrence.
– This establishes snow surface temperature anomaly as a better marker of an impending earthquake. We certainly need to investigate this phenomenon in detail by taking long-term seismic and thermal field measurements to understand the mechanism, its consistency, and reliability, says Anshuman Bhardwaj.
The research carried out by Anshuman Bhardwaj and his co-authors might get us one step closer to answering the riddle of how we can predict earthquakes, an answer that could save devastation and lives.
– Our results suggest that we should refrain from being pessimistic regarding precursory studies. We believe in the immediate need of holistic efforts whereby researchers of different backgrounds simultaneously explore several other precursors, says Anshuman Bhardwaj.
The research is published in the top-ranked remote sensing journal Remote Sensing of Environment and the article’s name is MODIS-based estimates of strong snow surface temperature anomaly related to high altitude earthquakes of 2015. Javier Martín-Torres, Professor of Atmospheric Science at Luleå University of Technolgy, is also among the authors.