Indonesia and the U.S. Team Up to Reduce Volcano Risk

By Jacob B. Lowenstern, Kasbani, John S. Pallister and David W. Ramsey. USGS Fact Sheet 2019–3074, April 2020.

Agung wakes up

Mount Agung on Bali had been quiet since its 1963 eruptions killed more than 1,000 people. In September 2017 it awoke, with hundreds of felt earthquakes alarming the tens of thousands living nearby. As steam rose, everyone asked: was Agung about to erupt again? Indonesia's Center for Volcanology and Geologic Hazards Mitigation (CVGHM) boosted monitoring and sent a rapid-response team from its headquarters in Bandung, on Java — and soon members of the USGS Volcano Disaster Assistance Program (VDAP) arrived from the United States to help.

The most volcanic nation

• 75 historically active volcanoes — the most of any country.
• Legendary eruptions: Tambora (1815), Krakatau (1883), and the Toba caldera in Sumatra (75,000 years ago), the largest eruption on Earth in the past 100,000 years.
• Recently: more than 36 volcanoes erupted in the past 20 years, some repeatedly, threatening millions.
• The response: from Bandung, dozens of staff coordinate 77 small observatories across a 5,000-kilometer (3,100-mile) archipelago.

A partnership of 50 years

For more than 50 years, the U.S. and Indonesia have worked together to reduce volcanic risk and save lives — today through an agreement between CVGHM and VDAP, funded by USAID and the USGS Volcano Hazards Program. Each year the two plan the next 12 months of training, field campaigns, equipment and priority topics.

Equipment: cooperation took off in 2004, with a plan to monitor volcanoes in Sulawesi and the remote northeast. With USAID equipment, the teams modernized real-time seismic monitoring at Soputan, Lokon-Empung and seven other volcanoes in North Sulawesi and the Sangihe Islands, then worked on Java, Bali, Lombok, Flores and Sumatra. From 2005 to 2018, they improved monitoring at 22 volcanoes, and USAID-donated equipment went in at more than 65.

VDAP staff and Indonesian colleagues review seismic data for earthquake patterns that may signal an eruption. Photo: Jeffrey Marso, USGS.

Training:

• joint workshops in Bandung and elsewhere on volcanic earthquakes and deformation, databases, hazard mapping, and eruption forecasting and modeling;
• field seminars on geologic mapping, aerial photography and photogrammetry, and volcanic gas;
• an annual 7-week course at the University of Hawaii's Center for the Study of Active Volcanism in Hilo and the USGS Cascades Volcano Observatory in Vancouver, Washington, partly taught by VDAP, bringing CVGHM staff together with observatory staff and students worldwide;
• travel to international meetings to share Indonesian research.

Merapi, 2010: evacuation saves lives

Often the two agencies collaborate without travel, using modern communications and satellites. On October 22, 2010, Indonesian scientists saw Merapi — about 4 million people live within 30 kilometers of its summit — producing far more intense earthquakes, gas and ground movement than usual. Using satellite data, including cloud-penetrating radar, VDAP and CVGHM tracked a fast-growing lava dome and recognized the danger of pyroclastic flows — scorching avalanches of ash and rock.

On November 4, CVGHM extended evacuations to 20 kilometers (12 miles) from the summit, up from 10. Hours later, Merapi's largest eruption in 100 years sent pyroclastic flows and surges as far as 15 kilometers (9 miles). 279,000 people were evacuated, and at least 10,000 to 20,000 people living in the devastated zone were saved.

Tools for forecasting

Forecasting depends on knowing a volcano's past and having tools to read its signals. VDAP builds and shares software used by observatories worldwide, and with global partners compiles databases of past eruptions that feed statistical models. In 2015, these helped VDAP and CVGHM estimate that lava at Sinabung, in northern Sumatra, would keep flowing for years — so long-term evacuation and community planning might be needed.

Installing a telemetered, solar-powered scanning spectrometer at Sinabung in 2016 to measure sulfur dioxide; the volcano has erupted continuously since 2013. Photo: Christoph Kern, USGS.

Kawah Ijen: a dangerous acid lake

At Kawah Ijen in eastern Java, a large acid crater lake masks changes in temperature and gas, and slugs of toxic gas periodically burst through, endangering miners, tourists and communities. New gas monitoring stations and a multinational workshop revealed how gas output and seasonal buildup work, and CVGHM staff are now expert at running USGS-designed, VDAP-donated gas instruments.

Many partners

No country faces more volcanic risk. With help from the United States (through VDAP), Japan, Belgium, Australia, France, Singapore and others, CVGHM has greatly expanded its networks and staff skills — and the partners gain experience testing instruments, refining software, improving community preparedness and studying some of the world's most active volcanoes.

Agung, 2017

As unrest grew in September and October 2017, more than 130,000 people were evacuated. CVGHM and VDAP installed and repaired equipment, upgraded computers, modeled eruption scenarios, analyzed seismic and deformation data, and developed new ways to sample gas in volcanic clouds. Agung calmed in mid-October, then erupted in late November 2017 and into the next year. The eruption was relatively small and no one was injured — and the episode strengthened a partnership decades in the making.

Sources

Based on Indonesia and the United States Team Up to Reduce Impacts from Dangerous Volcanoes, by Jacob B. Lowenstern, Kasbani, John S. Pallister and David W. Ramsey, USGS Fact Sheet 2019–3074, U.S. Geological Survey; a work of the United States government in the public domain. The fact sheet was published in English and Indonesian, and the import had taken the Indonesian text; this page is rewritten from the English PDF, with its two USGS photographs. Its cover photograph (Getty Images) and its Merapi map on a Google and DigitalGlobe image are not reproduced.