Local earthquakes boost volcanic activity in Indonesia, researchers have shown using satellite data. The finding could, they say, point to a predictive role for satellite imaging.
Volcanic activity in two ongoing eruptions, Merapi and Semeru on the Indonesian island of Java, increased following a local earthquake in May 2006 that measured 6.4 on the Richter scale. The flare-up began three days after the earthquake and lasted for nine days.
The researchers, led by Andrew Harris of the University of Hawaii, used thermal imaging data from an instrument on a NASA (the US National Aeronautics and Space Administration) satellite.
This provides near real-time data on global hotspots such as volcanic eruptions and wildfires. The team used data from a 35 day period, including the time of the earthquake.
"We found clear evidence that the earthquake caused both volcanoes to release greater amounts of heat, and lava emission surged to two to three times higher than prior to the tremor," Harris told NASA.
The researchers believe that the changes in eruption were due to seismic waves from the earthquake travelling to the area round the volcano and triggering an increased flow of molten rock.
But Dave Rothery, a vulcanologist in the Department of Earth Sciences at the UK-based Open University, warned that the study’s focus — one earthquake stimulating two volcanoes — could be a coincidence and more examples are needed.
The researchers say the work shows that satellite imaging could play a predictive role in eruptions, ultimately alerting people living near volcanoes to increased volcanic activity.
"I'm not sure we're up to early warning yet," Harris told SciDev.Net. "But immediately once an eruption begins we can detect its thermal signature, post its location on our global map, and perhaps alert people via automated email."
Rothery added that anyone with internet access could identify when volcanic activity is increasing in their area, information which could be "factored into decisions about evacuation".
The research was published in Geophysical Research Letters.
Reference: Geophysical Research Letters, doi: 10.1029/2006GL028251, 2007