Several earthquakes have demolished cities and rural areas in Nepal over the last few years, prompting international concerns about infrastructure and humanitarian needs of the country. Earthquakes have also hit locations in Alaska and Spain this year which were less devastating, but still concerning for residents involved in the quakes.
Researchers are working on developing remotely sensed maps that may assist locals in assessing damage and managing the aftermath with future earthquakes. Pulling data from the Italian Space Agency’s (ASI) COSMO-SkyMed system and the Japan Aerospace Exploration Agency’s (JAXA) ALOS-2 satellite, maps were created using a few different technologies including SAR, or synthetic aperture radar. SAR uses radar imaging from space using microwave signals that produce hyper-accurate images of Earth’s structures. SAR has also been used to track hurricanes and tornadoes as well as their damage in various parts of the world. Researchers were able to assess earthquake damage by comparing archival images showing the state of the landscape before the earthquake with imagery taken after the earthquake. A raster dataset created from the comparison is then symbolized with red indicating the areas of greatest potential damage and yellow areas of lesser but still significant damage. At 100-foot (30-meter) resolution, maps can detect landslide potential as well as show where buildings have collapsed during the quake.
NASA hopes these map will be used to show where the most damage has occurred after an earthquake so they can dispatch humanitarian and medical teams to the areas that need assistance the most. NASA’s maps were made available after Nepal’s most recent earthquake and helped multiple international humanitarian organizations coordinate their relief efforts. Local organizations have also taken the data used in the maps to continue providing assistance to locals who were deeply affected by the earthquake and who are still rebuilding.
The results of this research were recently published in the journal Seismological Research Letters.
NASA Damage Maps May Help in Future Quakes, Jet Propulsion Laboratory, January 29, 2016.
Yun, Sang-Ho, et al. “Rapid Damage Mapping for the 2015 Mw 7.8 Gorkha Earthquake Using Synthetic Aperture Radar Data from COSMO–SkyMed and ALOS-2 Satellites.” Seismological Research Letters 86.6 (2015): 1549-1556.