41: Growing unrest seen at many of the world’s volcanoes

January 26, 2013 – EARTH – Bárdarbunga (Iceland): Earthquakes at shallow depths (around 5 km) continue at reduced rate. Reventador (Ecuador): Activity continues, but likely has becoming more intermittent judging from the seismic signal. Visual observations are most of the time impossible. In a special bulletin posted yesterday IGEPN summarizes the beginning of the new eruptive phase: Seismicity began to increase significantly on January 22. The same day, volcanologists received the first reports of sounds of explosions and rumblings heard. On the evening of 22 Jan, new explosive activity produced an ash-rich plume rising 1500 m above the crater, and a new lava flow was detected on the southeastern flank, with its length estimated about 1500 m and the flow front at 2600 m elevation. Volcanologists have also could see on photographs taken that day, that the lava dome from the previous eruptive phase had grown. Kizimen (Kamchatka, Russia): The new lava flow from the summit on the north-eastern flank of the volcano continues to be active, KVERT reports. Incandescence of the volcano summit, hot avalanches, strong gas-steam activity and moderate levels of seismicity accompany this process. Tolbachik (Kamchatka, Russia): The eruption continues with little changes. Lava flows continue to erupt from the southern fissure, accompanied by stable, relatively high levels of tremor. Our French colleagues from activolcans received a brief eyewitness report: (translated from original) “The activity of the active cone was always very intense. Until yesterday (25 Jan) activity was marked by vigorous strombolian explosions that sometimes merged into lava fountains of 200-250 m height.” Kilauea (Hawai’i): Good magma supply continues to feed the lava lakes at the summit (Halema’uma’u) and the rift zone (Pu’u O’o), and lava flows that reach the ocean in multiple locations. Today, a small swarm of shallow quakes is occurring at the upper eastern rift zone a few km SE of the caldera. So far, 6 quakes in the magnitude 2 range have been recorded in this area and under the caldera itself today. Long Valley (California): Tiny quakes continue to be recorded under and near the Long Valley caldera. A small swarm is visible today in an area 20 km to the SE of Mammoth Mountain, at the SW limit of the caldera. Popocatépetl (Central Mexico): The number of gas/steam/minor ash emissions has jumped from rates of less than 1 every 2 hours during most of the past days to about 3 per hour (65 between 24-25 Jan). CENAPRED describes them of low to medium intensity and has observed continuing incandescence at the summit. The latest satellite data show an increased SO2 plume in correspondence with the elevated activity, and some volcanic quakes are visible at the current (now fixed?) seismogram. Santa María / Santiaguito (Guatemala): Explosions have been becoming more frequent; the volcano observatory reports weak to moderate ones with ash plumes rising up to 900 m during the past day. Effusion of lava flows continues. Fuego (Guatemala): During 24-25 Jan, it was not possible to observe the activity, but rumblings generated by explosions were heard. The lava flow length this morning was 800 meters, in southwestern direction. Nevado del Huila (Colombia): An SO2 plume detected on the latest NOAA satellite data suggests a phase of elevated degassing has been taking place. Sangay (Ecuador): A possible ash emission was reported last night (25 Jan) by Washington VAAC, but due to night time, satellite observation was not possible. A small thermal hot spot was detected at the summit, which suggests that probably weak or moderate strombolian activity has resumed in the crater.  –Volcano Discovery