Wednesday 5th January 2011 Volcanoes of Colombia Four volcanoes in Colombia have been placed on raised yellow alert. The volcanoes are Machin, Galeras, Huila, andl Ruiz. Earthquakes increased at Machin volcano on 31st December 2010. Over 4 days 367 volcano-tectonic earthquakes were detected south and southwest of the main dome. The largest event occurred at 5:22 pm on 1st January 2011, with a magnitude 2.3 and a depth of 3.3 km. The earthquake was felt by residents in vicinity of the volcano and in the municipality of Cajamarca (Tolima). In the week from 22 to 28 December 2010, 363 seismic events occurred at Nevado del Huila volcano, of which 72 were related to fracturing of rock and 291 caused by fluid dynamics in volcanic conduits. Nevado del Ruiz and Galeras have showed elevated but stable activity.
Having monitored the Katla Volcano since early 2010, a sudden grouping of earthquakes at and around the volcano during the past 24 hours is new cause for concern. Approximately 50 earthquakes have suddenly popped around the region. More alarming however are the 6 that have rumbled beneath and within the Katla volcano caldera itself, the most caldera quakes in one day since this author began monitoring it in May, 2010.
Eruptions continue at Kizimen volcano, Kamchatka with explosions and pyroclastic flows. Seismic activity is high, with volcanic tremor recorded. A hotspot was present over the volcano during the past week, which indicates a probable lava flow. On 1st January an ash plume extended 500 km SSW of the volcano and ashfall was recorded at Petropavlovsk-Kamchatsky, Yelizovo, Paratunka, Nalychevo and all Southern Kamchatka. On 5th January ash emissions extended over 500 km ENE of the volcano and ashfall was recorded in the Komandorsky Islands. On 5th December 2010 ash emissions reached a distance of 838 km NE of the volcano.
Tuesday 11th January 2011
Krakatau Volcano, Indonesia
Eruptions from Krakatau volcano, Indonesia have forced the evacuation of tens of thousands residents. Seven districts affected are Kalianda, Rajabasa, Katibung, Sidomulyo, Ketapang, Sragi and Palas. On Monday ash from Anak Krakatau continued to cover residential areas in parts of Banten province and South Lampung. Visual observations showed ash emissions reaching a height of 600 m and drifting east. Ashfall has affected the operation of seismometers on the volcano. Fisherman and tourists are advised to stay at least 2 km from the volcano.