Volcanos

Roundup of Global Volcanic Activity

Semeru (East Java, Indonesia): A pyroclastic flow (hot avalanche of fragmented volcanic material) occurred on the volcano's southern side yesterday morning, reaching 4.5 km length and producing an ash plume that rose to 26,000 ft (8 km) altitude. Darwin VAAC raised the aviation colour code to RED.

Another, smaller flow seems to have occurred today. The pyroclastic flow(s) were probably caused by sudden collapse of accumulated lava on the steep upper flank - inside the volcano's breached summit crater, a flat lava dome has been growing steadily during the past months and overspilling as viscous flow into the upper part of the ravine.

Momotombo (Nicaragua): Another explosion occurred at the volcano yesterday at 10:40 local time. It produced a pyroclastic flow that descended the NE flank through the prominent ravine that also had channeled the recent lava flow from 2015.

The pyroclastic flow, surrounded by yellow-brown ash, was likely the result of collapse of older material at the crater during the explosion. Whether and in which proportion fresh magma is involved in the current activity is difficult to say without an analysis of the ash. Glow continued to be visible at the crater during the night, suggesting that temperatures have increased and maybe magma is now at least close to the vents.