Using satellite information to rebuild after a disaster

Using satellite information to rebuild after a disaster
On 28 September 2018, the Indonesian island of Sulawesi was struck by a 7.5 magnitude earthquake followed by a tsunami that devastated the provincial capital of Palu, which lies at the head of a long narrow bay. This map shows the ground motion during the six months following the event and was obtained by processing Copernicus Sentinel-1  images acquired between October 2018 and April 2019. Results overlay a true-colour composite from the Copernicus Sentinel-2 mission. ESA and the Asian Development Bank have joined forces to help Indonesian authorities to use and interpret maps such as this to guide redevelopment plans. Credit: contains Copernicus Sentinel data (2018–19), processed by Planetek Rheticus Service

ESA and the Asian Development Bank have joined forces to help the Indonesian government use satellite information to guide the redevelopment following the earthquake and tsunami that devastated the provincial capital of Palu and surroundings last year.

On 28 September 2018, the Indonesian island of Sulawesi was struck by a 7.5 magnitude earthquake. The epicentre was on the island's northwest coast—77 km north of Palu, which lies at the head of a long narrow bay. The quake triggered a tsunami that swept huge surges of water—as high as 10 m—along the bay and swamped the city.

The combination of the earthquake, tsunami, soil liquefaction and landslides claimed well over 2000 lives, destroyed homes, buildings, infrastructure and farmland in several districts.

With the authorities and relief organisations having spent the last nine months dealing with the aftermath, the shift is now into the recovery phase. This includes the daunting job of rebuilding the areas that were decimated by the disaster—and the Asian Development Bank and ESA have joined forces to help the Indonesian government with the task in hand.

Through ESA's programme to support , the aim here is to provide environmental information products derived from Earth observation data and training in their use to Indonesia through the Asian Development Bank.

Using satellite information to rebuild after a disaster
On 28 September 2018, the Indonesian island of Sulawesi was struck by a 7.5 magnitude earthquake followed by a tsunami that devastated the provincial capital of Palu, which lies at the head of a long narrow bay. This terrain motion map uses Copernicus Sentinel-1 images acquired between October 2018 and April 2019 and provides information about the stability of individual buildings. Credit: contains Copernicus Sentinel data (2018–19), processed by Planetek Rheticus Service

The project, "Earth Observation for Sustainable Development—Disaster Risk Reduction," is led by the Spanish company Indra with the Italian SME Planetek as a partner along with the French Geological Survey BRGM who is the scientific advisor of ESA's Geohazard Exploitation Platform, an initiative that provides a cloud-processing service to support geological hazard mapping.

The main purpose of sharing these information products is to help the authorities better understand the hazards associated with , flooding and landslides so they can make more informed decisions in elaborating a redevelopment master plan.

Data from the Copernicus Sentinel-1 radar mission can detect ground movement of millimetres in and across wide areas and, therefore, provides a detailed picture of land deformation.

Ground-motion maps of before and after the earthquake have been produced through Planetek's automatic cloud-based "Rheticus Displacement' monitoring service. Accurate to a few millimetres, these maps are based on Copernicus Sentinel-1 radar data and are helping the authorities evaluate the effect that the disaster has had on the land surface stability.

Using satellite information to rebuild after a disaster
Following the earthquake and tsunami that hit the Indonesian island of Sulawesi in September 2018, ESA and the Asian Development Bank have been helping the authorities better understand the hazards associated with seismic activity, flooding and landslides through the use of satellite data. The project included a week-long training course in Jakarta, which explored services from ESA’s Geohazards Exploitation Platform. Ground displacement rate maps of Jakarta that use information from the Copernicus Sentinel-1 mission, as shown here, were used in the course. In this case displacement is largely a result of groundwater extraction. Values correspond to line-of-sight velocities. Local displacement patterns reach about 12 cm/year. The inset zooms-in over Jakarta’s harbour and is overlaid by displacement rates higher than 1.5 cm/year. Credit: Contains modified Copernicus Sentinel data (2019), processed by ESA, GEP, CNR-IREA & BRGM

In addition to these information products, the project also included a week-long course in Jakarta organised by the Asian Development Bank and the Indonesian National Institute of Aeronautics and Space. Attended by more than 60 representatives from numerous Indonesian institutions, experts from Indra, Planetek and BRGM explained technical details, methodologies and usage of these satellite data products.

Paolo Manunta, who helps ESA with on-site support to the Asian Development Bank, noted, "Users explained that they are particularly interested in the ground deformation maps—they offer great insight into how the land surface has changed and are essential for Indonesia to redevelop effectively."

The team has also suggested that the Indonesian government additionally use ESA's online Geohazard Exploitation Platform, which is designed to support the users looking at seismic risks, volcanoes, subsidence and landslides. It allows the seamless browsing, access and processing of vast amounts of satellite data, plus the software tools to extract useful knowledge.

The workshop included discussions on how space technology can support hazard and risk mapping in Indonesia and the user feedback obtained will serve as input for discussions between ESA, the Japanese Space Agency and the Asian Development Bank on how to further improve Earth observation for international .


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Citation: Using satellite information to rebuild after a disaster (2019, July 12) retrieved 24 July 2019 from https://phys.org/news/2019-07-satellite-rebuild-disaster.html
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