The twin earthquakes that struck Venezuela in June caused the ground to shift by as much as 60 centimetres, helping explain the extensive damage in Caracas and La Guaira, according to new observations from the NASA-ISRO Synthetic Aperture Radar (NISAR) satellite.
The findings mark the first time NISAR's Urgent Response system has been used to map surface displacement following a major earthquake, offering scientists valuable insights into how the Earth's surface moved during the disaster.
NISAR satellite captures ground movement after Venezuela earthquakes
Researchers analysed images captured by the NASA-ISRO Synthetic Aperture Radar (NISAR) satellite before and after the 24 June earthquake, comparing data collected on 13 and 18 June with images taken on 25 and 30 June.
The comparison enabled scientists to measure how the Earth's surface shifted as a result of the powerful tremors.
According to PTI, researchers used Interferometric Synthetic Aperture Radar (InSAR), a technique that compares repeated satellite observations to detect even small changes in the distance between the satellite and the ground.
Ground shifted by nearly 60cm near Caracas airport
The analysis showed that much of the movement occurred horizontally because the earthquake struck along a strike-slip fault.
According to NASA, one of the most significant displacements occurred south of Caracas' international airport, where the ground moved by approximately 60 centimetres.
"These are reasons why the damage in Caracas and La Guaira was so extreme," geophysicist Eric Fielding of NASA's Jet Propulsion Laboratory (JPL) was quoted as saying by PTI.
"InSAR tells us a lot about what happened during this earthquake," he added, according to PTI.
Scientists improve earthquake fault model using NISAR data
The earthquake occurred along a fault system that forms part of the boundary between the Caribbean Plate and the South American Plate.
According to scientists, faults in this region, including the San Sebastian fault system and possibly parts of the Bocono fault system, had been building up geological stress over a long period.
Using NISAR's observations, the US Geological Survey (USGS) refined its finite fault model, allowing researchers to better understand how the fault slipped beneath the Earth's surface during the earthquake.
"That is extremely helpful for the people who need to understand why the damage was so severe in that area," Fielding said, as quoted by PTI.
How NISAR's Urgent Response system helps after disasters
The displacement maps were generated through NISAR's Urgent Response (UR) system, which is designed to provide satellite data within 12 to 24 hours of a major natural disaster.
According to NASA, the rapid-response products are initially created using predicted satellite orbit information and are later refined with precise orbit data, usually within a day or two.
The fast delivery of satellite imagery is intended to support emergency responders, scientists and authorities as they assess damage and improve disaster response efforts.
What is the NASA-ISRO NISAR mission?
NISAR is a joint Earth observation mission developed by NASA and the Indian Space Research Organisation (ISRO). Equipped with advanced radar technology, the satellite can monitor subtle changes to the Earth's surface, including those caused by earthquakes, landslides, glaciers and vegetation changes.
The mission is expected to play a key role in disaster monitoring, environmental research and understanding geological hazards across the world.
Inputs from PTI
