New York: GPS and satellite data can be used in a real-time, coordinated effort to fully characterise a fault line within 24 hours of an earthquake, ensuring that aid is delivered faster and more accurately than ever before, new research shows.
For the study, assistant professor William Barnhart from University of Iowa used GPS and satellite measurements from the magnitude 6.0 earthquake in South Napa, California on August 24, 2014.
He created a 3D map of how the ground surface moved in response to the earthquake.
The map was made without using traditional rapid response instruments such as seismometers which may not afford the same level of detail for similar events around the globe.
"By having the 3D knowledge of the earthquake itself, we can make predictions of the ground shaking, without instruments to record that ground shaking, and then can make estimates of what the human and infrastructure impacts will be - in terms of both fatalities and dollars," said Barnhart who used data from the United States Geological Survey (USGS).
The study, that appeared in the journal Seismological Research Letters, shows that that GPS and satellite readings can be used as a tool to shorten earthquake response times.
The technique will be most useful in the developing world.
"The catastrophic magnitude 7.0 earthquake that hit Haiti in 2010 and killed nearly 316,000 people is the perfect example for the usefulness of this kind of tool," Barnhart said.
On an international scale, it dramatically reduces the time between when an earthquake happens, when buildings start to fall down, and when aid starts to show up, the authors wrote.
For the study, they first used GPS and satellite readings to measure the very small-millimetre-to-centimetre-sized-displacements of the ground's surface that were caused by the earthquake.
They fed those measurements into a mathematical equation that inverts the data and relates how much the ground moved to the degree of slip on the fault plane.
Slip describes the amount, timing, and distribution of fault plane movement during an earthquake.
This allowed the group to determine the location, orientation, and dimensions of the entire fault without setting foot on the ground near the earthquake.
The resulting model is a 3D map of fault slip beneath the Earth's surface.
The entire procedure takes only a few minutes to complete.
The information contained in Barnhart's study could be used to create further tools for predicting the economic and human tolls of earthquakes.