Volcano World

HVO reported that the eruption located at the W side of the down-dropped block within Kilauea?s Halema`uma`u Crater had ceased after activity declined over a few days. During 12-14 September multiple active vents, that were roughly E-W-trending and spanned a distance of about 750 m, produced lava fountains that rose as high as 10 m. Ramparts built by spatter were almost 20 m tall on the S sides (downwind side) of the vents. Lava from the vents flowed onto the N and W parts of the crater floor on 12 September, onto the N and E parts on 13 September, and only onto the W part by 14 September; the distances of the active flows progressively decreased. The area N of the active vents had become perched and was 3 m higher than the surrounding surface. Sulfur dioxide emissions averaged 20,000 tonnes per day (t/d) on the afternoon of 13 September, down significantly from 190,000 t/d measured just after the onset of the eruption. Effusion rates had decreased but remained at high levels. Vigorous spattering and lava fountains that rose 10-15 m were visible at the westernmost large spatter cone during 14-15 September. Minor spattering at the next cone to the E did not rise above its rim. Lava continued to flow from the vents and travel N and W, confined to the W part of the down-dropped block and the NE parts of Halema`uma`u. A laser rangefinder pointed at the W portion of the crater continued to record uplift from the magmatic intrusion beneath the caldera since the onset of the eruption; the total local uplift was 6 m by 13 September, 9 m by 14 September, and 10 m by 15 September. Field crews observed that eruptive activity had greatly diminished or ceased at several of the vents by the morning of 15 September. Lava was no longer flowing onto the crater floor but active lava was ponded in an area N of the vents. Intermittent spattering was visible overnight at the large, westernmost cone but beginning at around 0700 on 16 September webcam images recorded minor to no fountaining. By 1115 spattering ceased and by noon the ponded lava had stagnated. Tremor levels indicting fluid movement decreased during 15-16 September and retuned to pre-eruption levels by 1700 on 16 September. Sulfur dioxide emission rates had also decreased and were 800 t/d by 16 September, only slightly above the 100-200 t/d typical of non-eruptive periods. At 0902 on 17 September HVO lowered the Volcano Alert Level to Advisory (the second level on a four-level scale) and the Aviation Color Code was lowered to Yellow (the second color on a four-color scale).

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

The US Geological Survey reported that an eruption began at Ruby on 15 September. A submarine plume of discolored water was identified in satellite images at around 0650 but there was no activity above the water surface. Eruption signals began at 1427 on 15 September based on retrospective analysis of seismo-acoustic data from a geophysical monitoring station on Saipan, 50 km SE. The activity was also recorded on other regional geophysical monitoring networks in the Pacific. The submarine plume had detached from the source vent by the morning of 16 September and no additional activity was recorded by geophysical networks. The Volcano Alert Level was raised to Advisory (the second level on a four-level scale) and the Aviation Color Code was raised to Yellow (the second level on a four-color scale).

Source: US Geological Survey

JMA reported ongoing activity at Minamidake Crater (Aira Caldera?s Sakurajima volcano) during 11-18 September and incandescence at the crater was observed nightly. Sulfur dioxide emissions averaged 1,900 tons per day on 11 September. An explosion at 0018 on 11 September produced an ash plume that rose 1.1 km above the crater rim and ejected large blocks 300-500 m from the crater. An eruptive event at 1642 produced an ash plume that rose 1.3 km. At 2211 on 13 September an explosion produced an ash plume that rose 1.7 km and drifted N and ejected large blocks 500-700 m from the crater. The Alert Level remained at 3 (on a 5-level scale), and the public was warned to stay 2 km away from both craters.

Source: Japan Meteorological Agency (JMA)

PVMBG reported that the eruption at Dukono was ongoing during 13-17 September. Dense white-and-gray plumes rose as high as 350 m above the summit and drifted E and W. The Alert Level remained at Level 2 (on a scale of 1-4), and the public was warned to remain outside of the 2-km exclusion zone.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

KVERT reported that moderate explosive activity at Ebeko was ongoing during 7-14 September. A thermal anomaly was identified in satellite images during 9-11 September; weather clouds obscured views on other days. According to volcanologists in Severo-Kurilsk (Paramushir Island, about 7 km E), explosions during 10-11 and 13-14 September generated ash plumes that rose as high as 3 km (10,000 ft) a.s.l and drifted to the E. The Aviation Color Code remained at Orange (the third level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

INSIVUMEH reported that 4-10 explosions per hour were recorded at Fuego during 13-19 September, generating ash-and-gas plumes that rose as high as 1.1 km above the crater rim. The ash plumes drifted as far as 30 km W and SW, causing minor ashfall in areas downwind including Morelia (9 km SW), Panimach I and II (8 km SW), Palo Verde (10 km WSW), Sangre de Cristo (8 km W), El Porvenir (8 km SE), and Yepocapa (9 km WNW). Daily shock waves rattled structures in communities around the volcano and rumbling was often heard. Explosions caused daily block avalanches to descend the Ceniza (SSW), Seca (W), Trinidad (S), Taniluy (SW), Honda, Las Lajas (SE), and/or El Jute (ESE) drainages. The explosions also ejected incandescent material as high as 200 m above the summit.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

Although there was no eruptive activity reported, in a 19 September press release, PVMBG noted that the number of daily deep volcanic earthquakes at Gamalama increased in early September and remained above average. The seismic network recorded a total of 16 deep volcanic earthquake events on 8 September and an average of nine events per day through 18 September; 1-2 events per day are generally recorded. The number of earthquakes indicating emissions also increased during 8-18 September, though diffuse white plumes only rose as high as 100 m above the summit whereas typically they can rise as high as 300 m. PVMBG noted that the most likely hazard would be a phreatic event that could ejected material within the 1.5-km radius, though ash may be carried farther by wind. The Alert Level remained at 2 (on a scale of 1-4); visitors and residents were warned not to approach the crater within a 1.5-km radius.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

AVO reported that slow lava effusion likely continued at Great Sitkin during 13-19 September, producing a thick flow in the summit crater that mainly expanded E. A few daily earthquakes were recorded by the seismic network and seismicity was characterized as low. Weather clouds often prevented satellite and webcam observations, though no activity was observed on a few of the days with partly cloudy weather. The Volcano Alert Level remained at Watch (the third level on a four-level scale) and the Aviation Color Code remained at Orange (the third color on a four-color scale).

Source: US Geological Survey Alaska Volcano Observatory (AVO)

PVMBG reported that dense white gas-and-steam plumes from Karangetang were visible on most days during 13-19 September rising as high as 300 m above Main and North craters and drifting mainly NW, N, and NE. Weather clouds sometimes prevented views of the summit. According to news articles, seismicity during 1-7 September indicated lava from the SW side of Main Crater (S crater) continued to effuse but at a decreased rate, and that the number of earthquakes indicating avalanches had also decreased, according to PVMBG. Lava avalanches traveled as far as 1.5 km down the Batuawang and Kahetang drainages on the S flank and rarely descended the SW flank. Lava effusion at Main Crater was not visible during 8-15 September, though sounds of avalanches were sometimes intense, and rumbling was also occasionally heard. Incandescence emanated from both Main and North craters. The number of avalanches continued to decrease. The Alert Level remained at 3 (on a scale of 1-4) and the public were advised to stay 2.5 km away from Main Crater with an extension to 3.5 km on the S and SE flanks.

Sources: Antara News,Antara News,Antara News,Antara News,Antara News,Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)

KVERT reported that the explosive Strombolian eruption at Klyuchevskoy continued during 7-14 September. A daily bright thermal anomaly was identified in satellite images. Lava fountaining fed flows that advanced down the Apakhonchichsky and Kozyrevsky drainages on the SE flank. Plumes of resuspended ash drifted 550 km E and SE during 9-11 September. The Aviation Color Code remained at Yellow (the second level on a four-color scale). Dates are based on UTC times; specific events are in local time where noted.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)