Eruptions

Instituto Geofísico del Perú (IGP) reported that seismic activity at Ubinas remained elevated during 1-15 July; volcano-tectonic events averaged 279 per day and long-period events (indicating fluid movement) averaged 116 events per day. Minor bluish emissions rose from the crater. The Alert Level remained at Yellow (on a 4-level scale).

Sources: Instituto Geofísico del Perú (IGP),Instituto Geológico Minero y Metalúrgico (INGEMMET)

AVO increased the Aviation Color Code for Shishaldin to Yellow and the Volcano Alert Level to Advisory on 12 July following several weeks of increasing seismicity and elevated temperatures in the summit crater identified in satellite images. In addition incandescence in the crater was visible during an overflight. Seismic tremor continued to be elevated at least through 16 July.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

INGV reported that the paroxysmal explosive sequence at Stromboli on 3 July changed the morphology of the crater terrace. The rim of the terrace facing the Sciara del Fuoco was removed, and the N1 and N2 vents in Area N (north crater area, NCA) had enlarged and merged into one. After the paroxysmal event explosive activity rapidly decreased, though it remained more intense than normal. The vents of Area C-S (South Central crater area) produced explosions regularly during 8-14 July, and fed lava flows that traveled about halfway down the Sciara del Fuoco. Material from the lava-flow fronts rolled all the way to the coastline. A new lava flow from Area N (north crater area, NCA) began at 1900 on 14 July.

Source: Sezione di Catania – Osservatorio Etneo (INGV)

JMA reported that during 8-16 July very small eruptive events were detected at Minamidake crater (at Aira Caldera?s Sakurajima volcano), though none of them were explosive. The Alert Level remained at 3 (on a 5-level scale).

Source: Japan Meteorological Agency (JMA)

JMA reported that sulfur dioxide emissions at Asosan?s Nakadake Crater reached a high value of 2,300 tons per day on 12 July. Very small events ejected sediment during 13-16 July. The Alert Level remained at 2 (on a scale of 1-5).

Source: Japan Meteorological Agency (JMA)

Instituto Geofísico del Perú (IGP) reported that seismic activity at Ubinas remained elevated during 1-15 July; volcano-tectonic events averaged 279 per day and long-period events (indicating fluid movement) averaged 116 events per day. Minor bluish emissions rose from the crater. The Alert Level remained at Yellow (on a 4-level scale).

Sources: Instituto Geofísico del Perú (IGP),Instituto Geológico Minero y Metalúrgico (INGEMMET)

Centro Universitario de Estudios e Investigaciones de Vulcanologia – Universidad de Colima reported that intermittent steam-and-gas emissions, mainly from the NE side of the crater, and two small explosions were recorded during 5-12 July. Five lahars descended the Montegrande ravine. An overflight on 9 July revealed that the diameter of the vent had slightly increased, likely caused by subsidence, and other areas of minor subsidence within the crater were noted. An area of collapsed material on the outer W wall was also identified. Temperatures inside the crater were 116 degrees Celsius, lower than the temperature of 250 degrees Celsius recorded in May. The temperatures in the fumarolic area decreased from 202 degrees Celsius in May to 169 degrees. A thermal camera located S of the volcano recorded thermal anomalies associated with fumarolic emissions. Weather conditions sometimes prevented observations of the crater.

Source: Centro Universitario de Estudios e Investigaciones de Vulcanologia – Universidad de Colima

JMA reported that during 8-16 July very small eruptive events were detected at Minamidake crater (at Aira Caldera?s Sakurajima volcano), though none of them were explosive. The Alert Level remained at 3 (on a 5-level scale).

Source: Japan Meteorological Agency (JMA)

JMA reported that sulfur dioxide emissions at Asosan?s Nakadake Crater reached a high value of 2,300 tons per day on 12 July. Very small events ejected sediment during 13-16 July. The Alert Level remained at 2 (on a scale of 1-5).

Source: Japan Meteorological Agency (JMA)

Based on satellite and wind model data, and notices from PVMBG, the Darwin VAAC reported that during 11-16 July ash plumes from Dukono rose to altitudes of 1.8-2.1 km (6,000-7,000 ft) a.s.l. and drifted N and NE. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Sources: Darwin Volcanic Ash Advisory Centre (VAAC),Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)