Volcanos

Roundup of Global Volcanic Activity

Niigata-Yake-yama (Honshu): An increase in small earthquakes has been detected under the volcano located on the border between Niigata and Nagano Prefecture recently. In addition, a slight increase in fumarolic activity on the eastern side of the summit crater was noted and some inflation of the volcanic edifice recorded. According to the Niigata Meteorological Observatory monitoring the volcano, the number of volcanic earthquakes has been up to 4 times that of normal background levels, with up to 23 quakes recorded on a single day. Seismic activity has been dominated by low-frequency earthquakes, which are thought to reflect internal fluid movements (gasses, hot watery solutions, as well as magma). While the observed unrest is far from at alarming levels, they might reflect a change in the internal hydrothermal and /or magma storage system and could (but not necessarily must) be precursors to new activity at the surface.

Cleveland (Aleutian Islands, Alaska): The Alaska Volcano Observatory (AVO) raised the alert level of the volcano from yellow to orange after a new explosion was detected that had occurred this morning (18:44 AKDT local time). The size of the new eruption is unknown, but probably small; there are no direct observations of the remote volcano, but the explosion could be seen on both infrasound (air pressure) and seismic data. "There are no recent satellite views since the detected explosion, but previous Cleveland explosions have typically produced ash emissions", AVO wrote in its bulletin this morning.

Turrialba (Costa Rica): The volcano remains at elevated unrest and had a new small eruption yesterday noon (at 12:05 local time), producing ash emissions similar to those during the past weekend.