Volcano activity of October 24 - 30, 2012

This (almost) daily post intends to follow up the activity changes of volcanoes all over the world.
This post is written by geologist Richard Wilson who specializes in Volcano seismicity and Armand Vervaeck. Please feel free to tell us about new or changed activity if we haven't written about it. -

Volcano activity October 24 - 30, 2012

New Activity/Unrest

HEARD Southern Indian Ocean
According to Volcano Live, satellite imagery of Heard Island showed thermal anomalies on 21 and 24 September, and 10 and 19 October. NASA's Earth Observatory reported that a satellite image acquired on 13 October showed a possible dark area in the summit crater of Mawson Peak and hot surfaces within the crater, indicating the presence of lava in or just beneath the crater.

POAS Costa Rica
OVSICORI-UNA reported that a phreatic eruption at Poás was recorded at 1120 on 27 October. A phreatic eruption later that day (at 1757) ejected water, sulfur-rich sediments, and rock fragments out of the lake. The ejecta landed on the S and SW edges of the crater floor. According to a news article, local residents heard a loud rumble at about 0100 on 28 October; a phreatic eruption ejected sediment 500 m above the lake, and produced ashfall several hundreds of meters away.

Ongoing Activity

GALERAS Colombia
INGEOMINAS reported that during 24-30 October cameras around Galeras recorded daily emissions, including pulsating ash emissions. Multiple gas-and-ash plumes rose 500 m above the crater on 25 and 27 October. Seismicity fluctuated but was slightly lower compared to the previous week. Sulfur dioxide gas emissions were low to moderate. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").

ILIAMNA Southwestern Alaska
AVO reported that during 24-30 October seismicity at Iliamna remained slightly elevated. Clear satellite and web camera views showed nothing unusual. The Alert Level remained at Advisory and the Aviation Color Code remained at Yellow.

KARYMSKY Eastern Kamchatka (Russia)
KVERT reported moderate seismic activity from Karymsky during 19-26 October, indicating possible ash explosions. Satellite imagery showed a thermal anomaly on the volcano on 20 October. The Aviation Color Code remained at Orange.

During 24-30 October HVO reported that the circulating lava lake periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater. Occasional measurements indicated that the gas plume from the vent continued to deposit variable amounts of spatter, Pele's hair, and rock from the vent wall onto nearby areas. Cracking noises, audible from the Jaggar overlook and caused by rocks of the vent wall fracturing from the heat, emanated sporadically from the vent. Occasional collapses of rock from the vent walls triggered bursts of spatter that deposited a small amount of ejecta on the floor of Halema'uma'u Crater. On 25 October the lake rose to a level 27 m below Halema'uma'u Crater floor.
Lava flows accumulated at the base of the pali in the Royal Gardens subdivision and flowed across the coastal plain, but were 1.3 km from the coast. Flows also remained active on the pali. Activity at Pu'u 'O'o Crater remained elevated: the lava lake in the NE pit overflowed its rim, the vent on the N part of the crater floor produced lava flows, and lava fountaining and lava flows from the S vent were observed. Spattering was recorded from sources at the S and N edges of the crater floor.

CENAPRED reported that during 23-30 October seismicity at Popocatépetl indicated continuing gas-and-steam emissions that contained ash. Incandescence from the crater was observed at night during 23-24 and 28-30 October. Incandescent tephra was ejected from the crater on 26 October. The Alert Level remained at Yellow, Phase Two.

JMA reported that explosions from Sakura-jima's Showa Crater during 15-29 October explosions ejected tephra as far as 1.8 km from the crater. A small explosion from Minami-dake Crater occurred on 29 October. Based on information from JMA, the Tokyo VAAC reported that explosions during 24-27 and 29-30 October produced plumes that rose to altitudes of 1.5-3.4 km (4,000-11,000 ft) a.s.l. and drifted N, NE, E, SE, and S. During 24-25 and 29 October pilots observed ash plumes that rose to altitudes of 1.8-2.4 km (6,000-8,000 ft) a.s.l. and drifted N and SE.

Based on analysis of satellite imagery and information from INSIVUMEH, the Washington VAAC reported that on 24 October an 11-km-wide ash plume from Santa María drifted over 30 km SW. A diffuse gas-and-ash plume drifted 18 km S the next day.
INSIVUMEH reported that during 24-25 October explosions from Caliente dome produced ash plumes that rose 600 m and drifted W and almost 20 km S. Lava flows were visibly active on 26 October. Cloud cover prevented observations on 28 October. On 30 October a weak explosion generated an ash plume that rose 700 m and drifted SW. A few avalanches were produced by lava flows.

SHIVELUCH Central Kamchatka (Russia)
Based on visual observations and analyses of satellite data, KVERT reported that during 19-26 October a viscous lava flow continued to effuse on the NW flank of Shiveluch's lava dome, accompanied by hot avalanches and fumarolic activity. Satellite imagery showed a thermal anomaly on the lava dome during 20-23 October; clouds prevented views on the other days. The Aviation Color Code remained at Orange.

All information provided by the Smithsonian Institute