At Shinmoedake, the lava cake has an overflow front that does not progress much.
The gases, which are struggling to evacuate, caused two strong explosions on March 10, respectively at 1:55 and 4:25, according to the JMA. They were accompanied by projections of blocks up to 1,800 meters from the crater, and plumes of ash that rose to more than 4,500 meters above it.
The JMA extended the restriction zone from 3 to 4 km.
Professor Tetsuva Nakada of the Tokyo University Earthquake Research Institute, familiar with the Shinmoedake eruptions, confirms that gas pressure has increased in the lava-covered crater, generating an explosive eruption. In 2011, such explosions continued for two months.
Sources: JMA and NHK News
Explosive eruption of Shinmoedake volcano in the early March 10, 2018. Explosive sound reached the shooting point 30 seconds after the eruption. Fumes altitude 4,500 m. Before the eruption, a shooting star over the crater.
The Poas Acidic Lake is reduced to small, meteoric, sediment-rich basins of water, due to high evaporation rate, increasing ambient temperature, and solar radiation, coupled with typical low precipitation levels from the dry season, which runs from February to April.
These basins contain a milky pale green water, indicating a low-flow of low-temperature hydrothermal gas outlet through the bottom of the crater.
This phenomenon has occurred repeatedly in previous years, not in connection with eruptive activity, but in connection with polluting emanations and dangerous for the health of fragile people, the lake no longer playing its buffer role.
Source: Ovsicori & RSN