December 23, 2024

A Deadly Day on Mount Semeru: Destructive Rivers of Debris on Indonesian Volcano

December 7, 2021
Flows of superheated ash and tephra mixed with rain to produce destructive rivers of particles on the Indonesian volcano.
Mount Semeru, the highest and most active volcano on the Indonesian island of Java, has routinely spit up little, mostly safe plumes of ash and gas for many years. The situations altered on December 4, 2021.
Following a partial collapse of the top lava dome early in December, sensing units started to spot elevated seismic activity, according to the Volcanological Survey of Indonesia (PVMBG). After more of Semerus lava dome offered way, billowing fronts of superheated ash, tephra, soil, and other debris raced down a number of channels on the mountains southeastern flank.

Sometimes accelerating to speeds of hundreds of kilometers per hour, these masses of volcanic material and landscape particles can be difficult to outrun. The damage proxy maps above program areas on the surface area that were likely harmed by pyroclastic circulations and lahars in December 2021. Dark red pixels represent the most severe damage, while orange and yellow locations are reasonably or partially harmed. Each colored pixel represents a location of 30 meters by 30 meters (about the size of a baseball infield).

Often accelerating to speeds of hundreds of kilometers per hour, these masses of volcanic product and landscape particles can be difficult to outrun. They damage most living things in their course.
Given that heavy rains accompanied the eruption and preceded, the pyroclastic circulations mixed with big quantities of rainwater and morphed into muddy lahars that hurried down the mountain into inhabited locations. Lahars are mixtures of water and volcanic particles that act like rivers of concrete, flattening or burying much of what they experience.
The damage proxy maps above show locations on the surface area that were most likely harmed by pyroclastic circulations and lahars in December 2021. Dark red pixels represent the most serious damage, while orange and yellow areas are reasonably or partly damaged.
The slurry of particles that swept down Semeru proved devastating to villagers living around the mountains base in the Lumajang Regency, especially Curah Kobokan. According to The Jakarta Post, a minimum of 39 individuals have passed away. Great deals of homes were ruined or damaged, and numerous animals are amongst the eruptions victims.
The maps were derived from synthetic aperture radar (SAR) images gotten by the Copernicus Sentinel-1 satellites, run by the European Space Agency (ESA). The scientists utilized the Advanced Rapid Imaging and Analysis (ARIA) system originally established at NASAs Jet Propulsion Laboratory, California Institute of Technology, and modified at EOS-RS. The ARIA team is supported by NASAs Earth Science Disasters Program.
NASA Earth Observatory image by Lauren Dauphin, using modified Copernicus Sentinel information (2021) processed by ESA and evaluated by Earth Observatory of Singapore (EOS) in partnership with NASA-JPL and Caltech, Landsat data from the U.S. Geological Survey., and information from OpenStreetMap.