Satellite observations improve seismic monitoring, the response

Researchers at the University of Iowa and the US Geological Survey have found that data collected by orbiting satellites can provide more accurate information on the impact of large earthquakes, which could also contribute to more intervention. effective in case of emergency.

Satellite images provide detailed information on the location of earthquakes, the extent of surface deformation and the location of earthquakes relative to population centers, usually two to three days after the earthquake. . This information was then integrated into a set of Operational Response Guides managed by the USGS National Earthquake Information Center (NEIC), which is distributed to decision-makers, search and rescue operations, and to other groups.

In the article published online June 6 in the journal Remote sensing, the researchers determined that the satellite images collected from each earthquake provided new information that improved the analysis of its impact.

"This has led to more accurate estimates of the number of deaths and economic losses that it is essential to more accurately determine in the days and weeks that followed devastating earthquakes," said Bill Barnhart. , Assistant Professor in the Department of Earth Sciences and the Environment. to the user interface and a senior author of the study.

Ground seismometers, which measure the seismic activity in the world, constitute the pillars of the determination of the impact of an earthquake. But these instruments are not located everywhere, which can lead to incomplete information on the effects of certain earthquakes at a critical moment immediately after their occurrence. In addition, some earthquakes are more complex and can not be accurately measured by seismometers alone.

Earthquake scientists are increasingly turning to geodetic methods – the mathematical study of changes in the shape of the Earth – that use satellites and other instruments to supplement data collected by seismometers.

"Although this system is not yet fully operational, we are collaborating with the USGS to make the earthquake response operational with satellite imagery a systematic component of surveillance and response efforts to earthquakes. NEIC's land, "said Barnhart.

One example is Emma Mankin, a UI geoscience and senior student who will be graduating in December. Mankin processed radar images, or interferograms, of a magnitude 6.9 earthquake that struck Indonesia in August 2018. She then used this imagery to produce a model of the earthquake and his location. The USGS used this model directly to update its earthquake and earthquake impact forecasts incorporated into its disaster response systems.

"Emma's quick work on the earthquake in Indonesia has directly contributed to the operational analysis of a global earthquake," Barnhart said. "His contributions have improved estimates of the seismic impact of this event and demonstrated that these satellite approaches can provide actionable information for the benefit of society."

The document titled "Response to Global Earthquakes with Imaging Geodesy: Recent USGS NEIC Examples". He published online June 6 in the journal Remote sensing.