Friday, 7 October 2016

Volcanos

Roundup of Global Volcanic Activity

Colima | Mexico | 19.514°N, 103.62°W | Elevation 3850 m

The Unidad Estatal de Protección Civil de Colima reported that on 26 September seismicity at Colima increased, and crater incandescence was observed later that day. On 27 September small landslides originating from a new and growing lava dome traveled 100 m down the S flank. The exclusion zone was increased from 5 to 10 km in the Montegrande canyon; a 5-km exclusion zone was maintained in the other areas. According to news articles, incandescent landslides traveled down the S and SE flanks during 29 September-1 October. Gas-and-ash plumes rose 4 km and caused ashfall in nearby areas including La Becererra, La Yerbabuena, San Antonio, and El Jabali in the municipality of Comala, Montitlán in the municipality of Cuauhtémoc, and Juan Barragan in Tonila, Jalisco. On 1 October the Colima State government stated that the communities of La Yerbabuena (80 people) and La Becerrera (230 people) were preemptively evacuated, and the exclusion zone was extended to 12 km except on the Jalisco side (maintained at 7.5 km). A news article noted that Juan Barragan was also evacuated.

The Washington VAAC reported that on 29 September gas-and-steam emission possibly containing minor amounts of ash rose to an altitude of 4.9 km (16,000 ft) a.s.l. and drifted NW. On 30 September the webcam showed intense activity and crater incandescence, and gas-and-steam emissions that may have contained ash drifting WNW. An intense thermal anomaly was visible in short-wave infrared satellite images. Later that day an ash plume rose to an altitude of 5.8 km (19,000 ft) a.s.l. and drifted 35 km W. Possible emissions with ash were recorded by the webcam on 1 October; weather clouds obscured views of the crater. An ash plume detected in satellite images drifted almost 40 km S and SW. Later that day the webcam recorded explosions and pyroclastic flows. On 2 October ash plumes rose to altitudes of 6.1-8.2 km (20,000-27,000 ft) a.s.l. and drifted SW and W. Emissions later that day were mostly comprised of gas and steam; seismicity decreased, though a thermal anomaly continued to be detected in satellite images. On 3 October ash plumes rose to altitudes of 5.5-6.4 km (18,000-21,000 ft) a.s.l. and drifted 25-40 km SW and SWW. Ashfall was reported in areas on the S and SW flanks. Based on webcam views ash emissions rose to an estimated altitude of 5.5 km (18,000 ft) a.s.l. and drifted S on 4 October.

Iya | Flores Island (Indonesia) | 8.897°S, 121.645°E | Elevation 637 m

PVMBG reported that during 1 July-29 September variable-density white plumes rose as high as 150 m above Iya. During most of that period seismicity was at normal levels characterized by deep and shallow volcanic earthquakes each detected at a rate of less than 10 events per day. Between 1550 and 1800 on 29 September, however, the seismic network detected 17 volcanic earthquakes. Since the number of volcanic earthquakes was significant and above normal levels, the Alert Level was raised to 2 (on a scale of 1-4), and the public was warned not to approach the crater within a 2-km radius.

Katla | Iceland | 63.633°N, 19.083°W | Elevation 1490 m

The Iceland Met Office (IMO) reported that an intense seismic swarm began at Katla on 29 September. The activity intensified again at 1202 on 30 September with tremor and several earthquakes M 3 or larger. The Aviation Color Code was raised to Yellow, the second highest level on a four-color scale. On 3 October IMO stated that the seismic swarm was the largest one in decades, though it appeared to be over. According to a news article from 3 October popular travel destinations near the glacier had been and remained closed to traffic.

Rinjani | Lombok Island (Indonesia) | 8.42°S, 116.47°E | Elevation 3726 m

Based on data from the Mount Rinjani National Park, BNPB reported that as many as 1,023 tourists were on Rinjani when it erupted on 27 September; officially only 464 people were registered to make the 3-day trek to the volcano and back. Officials began the evacuation of tourists that day. According to a news article, 44 trekkers had still not returned to the entrance points by 1 October. The Alert Level remained at 2 (on a scale of 1-4); the public was warned not to approach the crater within a 3-km radius.

Tengger Caldera | Eastern Java (Indonesia) | 7.942°S, 112.95°E | Elevation 2329 m

Based on analyses of satellite images and information from PVMBG, the Darwin VAAC reported that on 29 September and 1 October ash plumes from Tengger Caldera’s Bromo cone rose to an altitude of 2.7 km (9,000 ft) a.s.l. and drifted E and SE.

Tungurahua | Ecuador | 1.467°S, 78.442°W | Elevation 5023 m

IG reported that during 27 September-4 October seismic activity at Tungurahua remained at moderate levels, characterized by 1-8 long-period earthquakes and up to three volcano-tectonic events per day. An hour-long period of tremor was recorded on 1 October. Minor fumarolic emissions rose above the crater rim.

Ubinas | Peru | 16.355°S, 70.903°W | Elevation 5672 m

According to IGP's Observatorio Vulcanológico del Sur (OVS) seismicity at Ubinas increased during 9-14 September, characterized by an increased number of volcano-tectonic and hybrid events. Volcano-tectonic vents also became more intense. A small thermal anomaly was detected on 20 September. According to a news article, an "exhalation" occurred at 1921 on 2 October, and was followed by explosions detected at 2250 that same day, and 0424 and 0552 on 3 October. The largest explosion, at 2250 on 2 October, emitted a dense ash plume that rose 1.7 km and drifted 10 km NE and NW, causing ashfall in Santa Rosa de Phara and Yanapuqui.

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