S.L. Andreastuti | USGS Science

USGS2019

The 2017-19 activity at Mount Agung in Bali (Indonesia): Intense unrest, monitoring, crisis response, evacuation, and eruption

After 53 years of quiescence, Mount Agung awoke in August 2017, with intense seismicity, measurable ground deformation, and thermal anomalies in the summit crater. Although the seismic unrest peaked in late September and early October, the volcano did not start erupting until 21 November. The most intense explosive eruptions with accompanying rapid lava effusion occurred between 25 and 29 November. Smaller infrequent explosions and extrusions continue through the present (June 2019). The delay between intense unrest and eruption caused considerable challenges to emergency responders, local and national governmental agencies, and the population of Bali near the volcano, including over 140,000 evacuees. This paper provides an overview of the volcanic activity at Mount Agung from the viewpoint of the volcano observatory and other scientists responding to the volcanic crisis. We discuss the volcanic activity as well as key data streams used to track it. We provide evidence that magma intruded into the mid-crust in early 2017, and again in August of that year, prior to intrusion of an inferred dike between Mount Agung and Batur Caldera that initiated an earthquake swarm in late September. We summarize efforts to forecast the behavior of the volcano, to quantify exclusion zones for evacuations, and to work with emergency responders and other government agencies to make decisions during a complex and tense volcanic crisis.

Scientific Reports↗

USGS2019

Character of community response to volcanic crises at Sinabung and Kelud volcanoes

Volcano disaster mitigation is a priority in Indonesia's national development plan due to the large number of active volcanoes, high frequency of eruptions and dense population within volcanic hazards zones. As a consequence of these factors and the many decades of experience in mitigation of volcanic risk, Indonesia demonstrates that effective community response is critical to avoid disasters. Understanding of hazards, risks and early-warning systems are the main factors in building an effective community response. The level of understanding of these factors is proportional to a community's independence in taking appropriate actions and is reflected in the community's preparedness. Further, the experience gained from responses to the eruptions of Sinabung and Kelud as well as from other Indonesian volcanoes shows that a local leader plays an important role in mobilizing a community. Such a leader utilizes knowledge of local culture (local wisdom) and an understanding of the community's character to encourage community members to participate and empower themselves. Sharing of information and the formulation of a disaster mitigation plan by government and community also results in a shared commitment to increase participation and community empowerment. Indonesia uses four volcano alert levels to activate community mitigation plans. In order of increasing criticality, these are: Normal, Advisory (Waspada), Watch (Siaga) and Warning (Awas). Implementation of policies, strategies and actions are tied to each level. In addition, mandatory actions by certain stakeholders are required at certain alert levels. These mandatory actions increase the effectiveness of disaster mitigation by both government and community. A comparison of the crisis responses of the Sinabung and Kelud communities is carried out here in order to better understand problems, learn lessons and improve the process of Indonesia's community mitigation policies. Local culture, the start time of community involvement (in normal versus crisis time), degree and level of government involvement, roles of local leaders, local perception of hazards, and political intervention are all factors that influence a community's response at the time of eruption. We stress that an understanding of the “ community character ,” which includes a number of cultural, social and knowledge parameters is essential for effective crisis management. The responses of Sinabung and Kelud illustrate both the key role of community in disaster mitigation and the synergy that can result from close coordination and collaboration between government and community.

Journal of Volcanology and Geothermal Research↗