Hakone volcano news & activity updates:
Hakone volcano (Japan): seismic unrest and eruption warning for Owakudani valley
Thursday May 07, 2015 09:21 AM | VON: T
Earthquakes under Hakone volcano (JMA)An eruption warning has been declared for the volcano, as increased seismic activity under the Ōwakudani hydrothermal field were registered during the past days and could herald sudden phreatic explosions.
The Owakudani valley lies north of the central lava domes inside the Hakone caldera. Seismicity started to increase in late April, consisting mostly of swarms of shallow quakes at 2 and 5 km depth. More intense swarms have occurred during the past days, triggering the Japan Meteorological Agency (JMA) to raise the alert level of the volcano to 2.
Simultaneously, slight deformation of the ground was detected and it appears that fumarolic activity has increased in the past days. Japanese authorities have closed access to the area, which is a popular tourist destination. After the deadly, sudden phreatic eruption of Ontake-san volcano last year, the risk of such eruptions has been taken very seriously.
Whether or not an eruption will occur at Hakone in the near future is impossible to say. Similar seismic crises have occurred in the past with no eruption following. The last known eruption at Hakone occurred in 950 AD.