Satellite technology and disaster management: Lombok earthquakes
In July and August this year, the Indonesian island of Lombok was hit by a series of high-intensity earthquakes that also affected other islands in Lombok province, West Nusa Tenggara. At least five of them (including pre-shocks, aftershocks, and main shocks) were of magnitude 5.9 (5.9 M) or greater. The worst of them occurred on August 5 at 6.9M and on August 19 at 7M, caused by two separate outages, according to ReliefWeb.
The number of casualties remains uncertain, although ReliefWeb says at least 555 people have been confirmed dead, more than 7,757 injured, 390,500 displaced and 80,500 houses damaged. Throughout the crisis, the Indonesian government declared a state of emergency which lasted for more than 3 weeks.
Due to damaged infrastructure, Lombok experienced an almost complete communication failure, which also affected the neighboring island of Bali due to landslides caused by earthquakes. All communications have been restored, and although the recovery process is still ongoing, most of Lombok has returned to everyday life.
The importance of satellite technology in disaster management
Satellites play a particularly important role in disasters such as the Lombok earthquakes and the recent Typhoon Manghkut, which hit the Philippines, Hong Kong, Macao, Taiwan and China, and has just dissipated. Communication satellites are the only option when terrestrial infrastructure and regular telecommunications services are disrupted, and satellite images taken from Earth observation satellites are the only way to get an overview of the earth. crisis.
Activation of disaster charters for satellite imagery
In the case of Lombok, international and regional disaster charters were activated immediately after the 6.9 million earthquake that rocked the island and surrounding areas on Sunday August 5. These charters and their affiliated organizations then provided satellite images to Indonesia through its space agency LAPAN, so that these images could be analyzed to give an accurate picture of the situation on the ground.
The International Charter “Space and major disasters” (known as the Disaster Charter), initiated by the European Space Agency (ESA) and the French space agency CNES, was activated on Monday 6 August. The request was made by the Asian Disaster Reduction Center (ADRC) based in Japan, on behalf of the Indonesian space agency LAPAN.
The Disaster Charter collected satellite images from its founding members including government bodies (mainly space agencies), as well as from charter partners such as Airbus, Digital Globe and the European Union’s Copernicus program, which makes satellite data available free of charge.
Sentinel Asia was also invoked, a regional initiative of the Regional Forum of Asia-Pacific Space Agencies (APRSAF) in which various space, environmental and environmental agencies collaborate for the purposes of disaster management and mitigation. Sentinel Asia uses data from satellites owned by its member organizations; these satellites include ALOS (Japan), IRS (India), THEOS (Thailand), KOMPSAT (Korea) and others. Sentinel Asia also obtains images and datasets from outside the region, such as NASA’s Landsat program and the United States National Geospatial-Intelligence Agency.
After the satellite images were received, several national and regional organizations began to analyze the pre and post disaster images to aid disaster relief and relief operations.
Images of the Disaster Charter, obtained by the CCRA, were distributed to LAPAN as well as to the Geoinformatics Center of the Asian Institute of Technology (GIC), based in Thailand, which was the Charter project leader. disasters for Lombok. The GIC, along with other organizations, then began to organize the data from all the different satellites.
The example below shows two maps produced by GIC, developed from satellite images from JAXA’s ALOR-2 satellite. Maps show the co-seismic deformation model after the earthquake (above), as well as the possible surface displacement (below).
Other organizations that have worked on geospatial products for rescue operations include Gadjah Mada University of Indonesia, United Nations Institute for Training and Research (UNITAR // UNOSAT), Copernicus Emergency Management Service (EMS) , LAPAN and the Regional Image Processing Service of France. and Remote Sensing.
One of the most important ways in which satellite imagery has aided rescue efforts has been to assess the severity of the damage in Lombok and its neighboring islands, and to identify possible areas for relocation and installation. displaced people.
To do this, LAPAN used high-resolution satellite images from the Airbus Spot 6 and Spot 7, TerraSAR-X satellites of the German space agency DLR and the Sentinel constellation of ESA. Pre-earthquake and post-earthquake images were compared to identify affected areas, including marking buildings that were damaged and buildings whose structure remained sound.
Damage to infrastructure severely affected communications in Lombok and surrounding areas. According to reports from the Indonesian Ministry of Communication and Information Technology (Kominfo), more than 642 base transceiver stations (BTS) were unusable out of the 6149 in Lombok as of August 20, and in total more than 1,200 (including other parts of West Nusa Tenggara and Bali) were damaged.
Work on the base stations began almost immediately by government personnel. Additionally, Indonesian satellite and telecommunications operators have been activated due to a regulatory clause in their standard operating procedure (SOP), which requires all operators to provide infrastructure and telecommunications support during a crisis. Companies involved included Telkom, Telkomsel, Indosat Oreedoo, XL Axiata, Smart Fren and H3i.
During this time, Kominfo relied on satellite communications and distributed 19 VSAT terminals, which were placed throughout the region, as well as 50 satellite phones. Of these, 5 were assigned to the Office of Disaster Management, 11 to military logistics and 34 to local governments.
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Separately, LAPAN used its LAPAN-A2 microsatellite (also known as LAPAN-ORARI), which carries a voice repeater for amateur radio communication. The satellite has, throughout its life, been used regularly by amateur radio operators and has brought together a community of enthusiasts both in Indonesia and in countries like India and Brazil.
When the crisis hit, the LAPAN satellite center called in volunteers to support relief efforts, including teaching staff how to use amateur radio communications. In 24 hours, more than 70 volunteers signed up. 19 additional repeaters were installed throughout the island and the dual-band walkie-talkies were set to receive at a frequency of 435.880 MHz and transmit at a frequency of 145.880 MHz.
BTS communications were fully restored on Tuesday August 28, which ensured 100% health of 2G, 3G and 5G networks.
Now that life in West Nusa Tenggara is slowly returning to normal, satellites still have a role – satellite imagery continues to provide stakeholders with a tool to find and understand earthquakes and the fault lines that caused them. Earth observation will also be used to accelerate recovery efforts, for example to revive Lombok as a popular tourist destination, and for urban planning purposes. Satellite communications, on the other hand, remain a necessity in Indonesia due to its large number of islands spread over an immense territory.