Smithsonian/USGS Weekly Volcanic Activity Report 14-20 March 2012

The latest Smithsonian Institution and United States Geological Survey Weekly Volcanic Activity Report has been published by the Global Volcanism Program, covering the week 14-20 March 2012. The report is compiled by Sally Kuhn Sennert. Among the highlights of this week:

• A plume, probably water vapour, seen from Iliamna, where seismicity remained elevated
• Seismicity decreased at Nevado del Ruiz but significant gas emissions continued
• Etna continued lively with lava flows and fountaining, and strong ash emission
• Daily explosions at Shiveluch produced plumes which reached 3-5 km altitude

Click on the map for a larger version (1211 x 784 pixels).

The Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report for 14-20 March 2012 is now available on the Global Volcanism Program website. The following is a summary and not a substitute for the full report.

• The current report: Weekly Volcanic Activity Report.
• Previous reports: Weekly Reports Archive.
• The SI/USGS map of volcanoes discussed this week.

New activity/unrest: Iliamna (Alaska, USA), Nevado del Ruiz (Colombia).

Ongoing activity: Cleveland (Alaska, USA), Etna (Italy), Karymsky (Russia), Kilauea (Hawaii, USA), Kizimen (Russia), Popocatépetl (Mexico, Puyehue-Cordón Caulle (Chile), Sakura-jima (Japan), Shiveluch (Russia), Soufrière Hills (Montserrat), Tungurahua (Ecuador), Villarrica (Chile).

Note: ‘a.s.l.’ = ‘above sea level’.

NEW ACTIVITY/UNREST

Iliamna (Alaska, USA). AVO reported that during 9-20 March seismicity at Iliamna was above background levels. Satellite images acquired during 9-16 March showed a plume drifting 56 km downwind that was likely water vapor. The report noted that long-lived fumaroles at the summit of Iliamna frequently produced visible plumes, but the current plume appeared to be more robust than usual. Scientists aboard an overflight on 17 March observed vigorous and plentiful fumaroles at the summit, consistent with the elevated gas emissions. Gas measurements indicated that the volcano was emitting elevated levels of sulphur dioxide and carbon dioxide. The Alert Level remained at Advisory and the Aviation Colour Code remained at Yellow. [GVP: Iliamna]

Nevado del Ruiz, (Colombia). According to INGEOMINAS, the Observatorio Vulcanológico and Sismológico de Manizales reported that during 12-18 March seismicity at Nevado del Ruiz decreased but gas emissions remained at significant levels. Gas plumes rose 2 km above the crater and sulphur dioxide odors were reported by local people. The Alert Level remained at III (Yellow; ‘changes in the behaviour of volcanic activity’). [GVP: Nevado del Ruiz]

ONGOING ACTIVITY

Cleveland (Alaska, USA). AVO reported that a small explosion from Cleveland was detected at 1455 on 13 March by distant seismic stations and infrasound arrays. Weather conditions prevented the detection of a possible eruption cloud in satellite images or by visual observation of the summit. No other activity was detected during 14-19 March. The Volcano Alert Level remained at Watch and the Aviation Colour Code remained at Orange. No current seismic information was available because Cleveland does not have a real-time seismic network. [GVP: Cleveland]

Etna (Italy). Sezione di Catania – Osservatorio Etneo reported that the twenty-second paroxysmal eruptive episode since January 2011 took place at New SE Crater (New SEC) of Etna during the morning of 18 March following two weeks of quiescence. Roaring from high-pressure degassing was heard on 16 March. The next day there was incandescence and multiple vapour clouds with minor ash content that rose from New SE Crater. In the early hours of 18 March the incandescence intensified due to Strombolian activity on the crater floor, and volcanic tremor amplitude rapidly increased. Strombolian activity continued to intensify, and just before 0700 lava flowed through the deep breach in the SE crater rim. At about 0825 the ash content in the gas plume rising from the crater became more significant and pulsating lava fountains from a vent on the crater floor rose about 100 m high. Shortly before 0900 two vents were active within the crater and a jet of lava was emitted from another vent within the breach in the SE crater rim. During 0900-0915 lava fountaining was essentially continuous from all three vents. An intense shower of coarse-grained pyroclastic material falling onto the N and NE flanks of the cone generated avalanches and clouds of rock and dust, which traveled to the base of the cone. A plume rose 4-5 km above Etna and drifted E. Ash and lapilli fell mainly in the area between the villages of Zafferana Etnea and Sant’Alfio, extending toward the Ionian Sea between Riposto and Pozzillo. The main lava flow descended the steep W slope of the Valle del Bove. Several lava lobes, however, took a more northerly path to areas covered with thick snow. The interaction of the lava and snow led to rapid melting of the snow, generating small lahars, and strong explosions that produced ground-hugging vapour-and-ash clouds resembling pyroclastic flows, which repeatedly descended on the floor of the Valle del Bove. The vapour-and-ash clouds rose 1-1.5 km above the floor of the Valle del Bove. This phenomenon continued intermittently for some time after the cessation of the lava fountaining and ash emission, until about 1130. Lava fountaining and strong ash emission continued without significant variations until about 1040; afterwards the activity rapidly diminished in intensity, and the last ash clouds were observed around 1110. Similar to the previous episodes, the lava that flowed through the breach in the SE crater rim advanced for several hours after the cessation of the paroxysmal activity into the upper part of the Valle del Bove. The lava reached a distance of about 4 km from the source, stagnating S of Monte Centenari. A small lava flow, emitted from a fracture on the N flank of the cone, followed the same path as a flow emitted from the same fracture during the 4 March paroxysm, and traveled a few hundred metres. [GVP: Etna]

Karymsky (Russia). KVERT reported that during 9-16 March seismic activity from Karymsky continued to be detected and indicated that possible ash plumes rose to an altitude of 3.1 km (10,100 ft) a.s.l. on 14 March. Satellite imagery showed a thermal anomaly on the volcano during 10-13 March. The Aviation Colour Code remained at Orange. [GVP: Karymsky]

Kilauea (Hawaii, USA). During 14-20 March, HVO reported that the lava lake periodically rose and fell in the deep pit within Kilauea’s Halema’uma’u Crater. Almost daily measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and fresh spatter nearby. Incandescence was visible from both a small pit on the NE edge and a small spatter cone on the SE edge of the Pu’u ‘O’o crater floor, and on the upper part of the lava-tube system on the E flank. Lava flows continued to advance down the pali and across the coastal plain, and were about 2 km from the coast. [GVP: Kilauea]

Kizimen (Russia). KVERT reported moderate seismic activity at Kizimen during 9-16 March and a large thermal anomaly that was detected in satellite images. Video and satellite observations indicated both continued effusion of a large lava flow on the E flank and hot avalanches. Strong gas-and-steam activity was observed with the video camera. The Aviation Colour Code remained at Orange. [GVP: Kizimen]

Popocatépetl (Mexico). CENAPRED reported that during 14-20 March steam-and-gas emissions rose from Popocatépetl and incandescence from the crater was observed at night. Emissions contained small amounts of ash on 14 March. On 18 March emissions again contained a small amount of ash and were accompanied by increased incandescence from the crater. [GVP: Popocatépetl]

Puyehue-Cordón Caulle (Chile). Based on seismicity detected during 13-20 March, OVDAS-SERNAGEOMIN reported that the eruption from the Cordón Caulle rift zone, part of the Puyehue-Cordón Caulle volcanic complex, continued at a low level. Plumes observed during 13-16 March in web camera and satellite images rose 0.4-1.2 km above the crater, and drifted 30 km E on 14 March, 20 km N on 15 March, and 17 km NNE on 19 March. Incandescence from the crater was observed during 13-14 and 16-20 March. The Alert Level remained at Red. [GVP: Puyehue-Cordón Caulle]

Sakura-jima (Japan). JMA reported that on 12 March an explosion from Sakura-jima’s Showa crater ejected tephra that landed as far as 2 km from the crater. Based on information from JMA, the Tokyo VAAC reported that during 14-21 March explosions often produced plumes that rose to altitudes of 1.5-2.7 km (5,000-9,000 ft) a.s.l. and drifted N, NW, and SE. Pilots observed ash plumes during 18-20 March that rose to altitudes of 1.2-4 km (4,000-13,000 ft) a.s.l. and drifted SE and E. [GVP: Sakura-jima]

Shiveluch (Russia). KVERT reported that activity at Shiveluch increased on 10 March and during 10-14 March daily explosions produced ash plumes that rose to altitudes of 3-5 km (10,000-16,400 ft) a.s.l. During 10-16 March ground-based observers and satellite imagery indicated that a viscous lava flow continued to effuse in the crater formed during a 2010 eruption. Satellite imagery showed a thermal anomaly on the volcano and ash plumes that drifted 64 km NE and SE during 10-11 and 13 March. The Aviation Colour Code remained at Orange. Based on information from Yelizovo Airport (UHPP) and satellite images, the Tokyo VAAC reported that an ash plume rose to an altitude of 5.2 km (17,000 ft) a.s.l. and drifted SE. [GVP: Shiveluch]

Soufrière Hills (Montserrat). MVO reported that on 9 March at 1720 a small pyroclastic flow from the Soufrière Hills lava dome traveled about 1.75 km W down Spring Ghaut and produced a small ash cloud that rose 1.2 km and drifted W. During 9-16 March activity was at a low level. The Hazard Level remained at 2. [GVP: Soufrière Hills]

Tungurahua (Ecuador). IG reported that, although visual observations of Tungurahua during 14-20 March were mostly limited due to cloud cover, steam plumes were noted on 18 March which drifted W. On 19 March explosions were detected by the seismic network. During brief periods where the crater was visible, observers noted incandescence emanating from the crater and a few blocks rolling 200 m down the flank. Slight ashfall was reported in Choglontus (8 km SW), Manzano (8 km SW), and Penipe (15 km SW) the next morning. [GVP: Tungurahua]

Villarrica (Chile). According to Projecto Observación Visual Volcán Villarrica (POVI), spattering from Villarrica’s lava lake was visible during 7-9 March. Four small ash emissions were observed during 13-14 March. [GVP: Villarrica]

The foregoing is a summary of the Smithsonian Institution/United States Geological Survey Weekly Volcanic Activity Report covering 14-20 March 2012. It is provided for information only, and is based on but not a substitute for the full report, which comes with its own criteria and disclaimers. The map base is derived from the Smithsonian Institution/USGS/US Naval Research Laboratory This Dynamic Planet website.

For all our coverage of the SI/USGS Weekly Volcanic Activity Reports: Weekly Volcanic Activity Reports « The Volcanism Blog.