CVGHM lowered the Alert Level for Gamkonora from 3 to 2 (on a scale of 1-4) on 24 July based on visual observations and a decrease in seismicity. That followed a sharp drop in seismicity during 8-23 July, a decline both in terms of the number of events and their energy. Later, during 16-23 July, when breaks in inclement weather took place, observers saw white plumes rising to altitudes of 5.6 km (18,400 ft) a.s.l.
An important new eruption initiated at Kilauea very early on 21 July. It occurred along the E rift zone from fissures trending ENE for several kilometers from Pu'u O'o. The fissures caused drainage of both the West Gap lava lake and the Puka Nui pit.
Ol Doinyo Lengai is frequently the scene of fluid but very small volume lava flows in its summit crater, including a few that passed over the crater rim and begun the long descent down the mountain. As noted here last week, news reports had indicated that products of the volcano's 19-July eruption had entered inhabited areas. Subsequent investigations have cast doubt on those earlier claims.
Based on a pilot report, the Darwin VAAC reported that an ash plume possibly from Raung rose to an altitude of 1.5 km (5,000 ft) a.s.l. Ash was not visible on satellite imagery.
Based on a Significant Meteorological Information (SIGMET) advisory, the Buenos Aires VAAC reported that ash plumes from Ubinas rose to an altitude of 5.8 km (19,000 ft) a.s.l. on 23 and 25 July. The plumes drifted SE and S, respectively.
A KVERT report issued for Karymsky on 27 July stated the following, "The eruption of the volcano continues. Ash explosions up to 6 km (or 19,700 ft.) a.s.l. are possible at any time. The activity of the volcano could affect low-flying aircraft in the vicinity of the volcano."
Based on pilot observations, the Washington VAAC reported that an ash plume from Sangay rose to an altitude of 6.7-8.2 km (22,000 to 27,000 ft) a.s.l. on 28 July. Ash was not detected on satellite imagery but a weak hotspot could be seen.
KVERT reports noted that seismic activity at Shiveluch continued above background levels during 20-27 July. Based on seismic interpretation, during this interval ash plumes rose to an altitude of 6 km (19,700 ft) a.s.l. Gas-and-steam plumes with some ash rose to altitudes of 3.0-4.5 km (9,800-14,800 ft) a.s.l. during 20-24 July.
Wed, 25 Jul 2007, 06:00
MVO reported that based on visual observations, the lava dome at Soufrière Hills changed very little during 25-26 July. Seismic activity was very low and low-level rockfall activity continued. The Alert Level remained elevated at 4 (on a scale of 0-5).
Read allWed, 25 Jul 2007, 06:00
Data from deformation-monitoring instruments indicated that during 25-31 July lava-dome growth at Mount St. Helens continued. Seismicity persisted at low levels.
Read allWed, 25 Jul 2007, 06:00
Based on information from JMA and a pilot report, the Tokyo VAAC reported that an ash plume from Suwanose-jima rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted SW on 26 July. Ash was not visible on satellite imagery.
Read allWed, 25 Jul 2007, 06:00
As noted by the IG in their daily reports covering 25-31 July, Tungurahua emitted a substantial number of small ash-bearing explosions and several unusually large ones as well. Based on ground observer estimates, many plumes during the reporting interval rose to 2-3 km above the crater rim (up to ~1 mile above the crater) and dropped ash on towns located on the volcano's flanks.
Read allMon, 23 Jul 2007, 01:50
On July 21, the activity inside Pu'u 'O'o cone ceased, and a new intrusion made its way to the surface in the area east of the cone and uprift from Kupaianaha shield (active in the 1990s). More news and photographs about this remarkable change in the ongoing eruption can be found at HVO's update pages: http://volcano.wr.usgs.gov/hvostatus.php.
Mon, 23 Jul 2007, 01:46
As more news has become available, the news about an effusive flank eruption at Lengai around 15 July turns out to be probably false. The observed "ashcloud" was dust from a landslide. This demonstrates how difficult it is in this area to have robust information. The ongoing seismic activity in the Gregory Rift, however, is quite peculiar.
Read allWed, 18 Jul 2007, 06:00
According to news reports, an eruption began at Ol Doinyo Lengai around 19 July, forcing villagers living near the volcano to evacuate. An article stated that, "...more than 1,500 people, most of them Maasai families, vacated their homes in Ngaresero, Orbalal and Nayobi villages following the tremors that triggered the volcanic eruption." "Villagers are reported to have heard roaring...before the volcano started discharging ash and lava." There were reports of a damaged school and two injuries, but no reports of deaths.
Read allWed, 18 Jul 2007, 06:00
Based on a Significant Meteorological Information (SIGMET) advisory, the Buenos Aires VAAC reported that an ash plume from Ubinas rose to an altitude of 6.1 km (20,000 ft) a.s.l. and drifted SE on 22 July. Ash was not identified on satellite imagery.
Read allWed, 18 Jul 2007, 06:00
Seismic activity at Karymsky was above background levels during 13-20 July, with 500-900 shallow earthquakes occurring daily. Based on seismic interpretation, ash plumes may have risen to altitudes as high as 4.5 km (14,800 ft) a.s.l. Ash plumes drifted SE and SW and a thermal anomaly in the crater were visible on satellite imagery during 14-18 July.
Read allWed, 18 Jul 2007, 06:00
KVERT reported that seismic activity at Kliuchevskoi was at background levels during 13-20 July. Based on observations of satellite imagery, ash plumes drifted E on 13 July and a thermal anomaly in the crater was noted during 13-20 July. Ash plumes rose to an altitude of 5.5 km (18,000 ft) a.s.l. and drifted SE and E during 13-15 July, according to video and visual observations.
Read allWed, 18 Jul 2007, 06:00
Based on pilot reports and satellite image observations, the Buenos Aires VAAC reported that an ash plume from Lascar rose to altitudes of 7.6-9.1 km (25,000-30,000 ft) a.s.l. on 18 July and drifted NE.
Read allWed, 18 Jul 2007, 06:00
Based on pilot observations, the Washington VAAC reported that an ash plume from Sangay rose to an altitude of 5.5 km (18,000 ft) a.s.l. and drifted W on 23 July. Ash was not detected on satellite imagery.
Read allWed, 18 Jul 2007, 06:00
KVERT reported that seismic activity at Shiveluch continued above background levels during 13-20 July. Based on seismic interpretation, ash plumes rose to an altitude of 6 km (19,700 ft) a.s.l. during the reporting period.
Read allWed, 18 Jul 2007, 06:00
MVO reported that during 13-24 July, the lava dome at Soufrière Hills changed very little, based on visual observations. Seismic activity was very low and low-level rockfall activity continued. Heavy rainfall generated lahars in E drainages on 19 July.
Read allWed, 18 Jul 2007, 06:00
Data from deformation-monitoring instruments indicated that during 18-24 July lava-dome growth at Mount St. Helens continued. Seismicity persisted at low levels, punctuated by M 1.5-2.5, and occasionally larger, earthquakes. Clouds inhibited visual observations.
Read allWed, 18 Jul 2007, 06:00
IG reported that during 18-24 July, intermittently visible ash plumes from Tungurahua rose to altitudes of 5.2-8 km (17,100-26,200 ft) a.s.l. and drifted NW, W, and SW. Ashfall was reported from areas SW and W during 19-21 and 24 July.
Read allWed, 18 Jul 2007, 06:00
AVO raised the Volcanic Alert Level for Cleveland from Advisory to Watch and the Aviation Color Code from Yellow to Orange on 20 July. The change in Alert Level was based on the presence of an intense thermal anomaly in the crater and associated steam-and-gas plume observed on satellite imagery. The thermal anomaly continued to be detected on satellite imagery during 22-23 July.
Read allWed, 18 Jul 2007, 06:00
INSIVUMEH reported that during 17-18 July, gas plumes from Fuego rose to an altitude of 3.9 km (12,800 ft) a.s.l. and drifted SW. On 18 July, a hot lahar, 20 m wide and 1.5 m high, carried blocks 1-1.5 m in diameter to the W down the Santa Teresa ravine.
Read allWed, 18 Jul 2007, 06:00
During 18-21 July, the E vent and dominant W vent in Kilauea's Pu'u 'O'o produced lava flows. On 18 July, new vents opened in the Puka Nui pit, in the SSW area of Pu'u 'O'o crater, and produced lava flows that ponded. On 20 July, a vent high on the S crater wall, adjacent to the Puka Nui Gap pit, produced spatter and propelled lava bombs 10 m into the air.
Read allTue, 17 Jul 2007, 19:36
The lava lake inside the Puu Oo crater as on 11 July.
Over the past week, the lava lake inside the Puu Oo crater became less and less alimented, dropped several meters inside an 8-shaped system of levees. It remaining active in this smaller area, fed by the eastern vent, but by yesterday, its activity appears to have ended according to information from HVO. Instead, new vents have become active in the western area of the Puu Oo cone.
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Source: HVO
