Qantas Airlines reported to the Darwin VAAC that an ash cloud to about ~3 km a.s.l. was observed on 2 August at 1450. Analysis of satellite data did not show ash.
Volcanic and seismic activity at Soufrière Hills during 26 July-2 August continued at an elevated level. The swarm of low-amplitude long-period earthquakes that began on 19 July continued, but decreased during the last 3 days of the report period. A flight on 1 August revealed that the new extrusion lobe on the N side of the summit had a broad whaleback form.
During 27 July-2 August, seismicity remained above background levels at Shiveluch and a lava dome grew in the active crater. Individual earthquakes of M 1.9-2.4, as well as a number of smaller earthquakes at depths of 0-6 km, were recorded. Other local seismic signals indicated that possible weak, ash-poor explosions rose to 1 km above the dome.
Activity at Semeru remained at a higher level than normal, but thick fog obscured the view. Seismicity increased compared to the previous week and was dominated by 744 explosion earthquakes. Semeru remained at Alert Level 2 (on a scale of 1-4).
A helicopter flight over Nyiragongo on 1 August revealed a thick, dense plume rising from the crater at a high velocity. The inner crater was completely filled with dispersed gas, preventing visibility of any fresh lava that may be in the crater. No red glow has been seen during recent nights, but the permanent sustained tremor recorded on all stations confirmed that the volcano remained active with magma moving beneath it.
Helicopter flights on 1 and 3 August revealed that the eruption that began on 25 July at Nyamuragira continued at a high rate. Two volcanic cones were visible growing on the eruptive fracture. The cones were built by the accumulation of spatter and ash from two very active 100- to 200-m-high lava fountains.
During 29 July-4 August, incandescent lava avalanches traveled predominately down Merapi's SW flank into the upstream portions of the Sat, Lamat, Senowo, and Bebeng rivers. The avalanches reached a maximum run-out distance of ~2.6 km. A thin white plume rose ~400 m above the summit.
By 6 August, only the the Wilipe`a entry was active at Kilauea, with five or six spigots sending lava off the leading edge of the bench into the water. The West Highcastle bench was steaming but had no lava. At the Highcastle kipuka, two actively advancing lobes of lava were found, one 160 m and the other 170 m from the western and eastern remnants, respectively, of the Chain of Craters Road, themselves only 40-60 m from water.
Wed, 31 Jul 2002, 06:00
During 27 July-2 August, seismicity remained above background levels at Karymsky. Local, shallow seismic events decreased from 250 to 150 events per day. The character of the seismicity indicated that weak ash-and-gas explosions and gas blow-outs possibly occurred.
Read allWed, 31 Jul 2002, 06:00
According to VSI, a small ash plume reached 400 m above the S part of the main crater of Karangetang this week. Crater II produced a small ash plume to 200 m. Seismicity decreased compared to the previous week. Karangetang remained at Alert Level 2 (on a scale of 1-4).
Read allWed, 31 Jul 2002, 06:00
Activity continued at Etna during 31 July-6 August with brown ash explosions from Bocca Nuova crater. SO2 emissions were detected from Voragine crater on 4 August. Strong explosions originating in Northeast Crater were felt during the afternoon of 6 August.
Read allWed, 24 Jul 2002, 06:00
Beginning on 22 July there was an increase in the number of explosive events at Tungurahua in comparison to the previous week. Explosions on 23 and 24 July reached an average height of ~2 km above the summit and drifted to the NW, W, and SW. Small amounts of ash fell in the sectors of Riobamba, SW of the volcano, and Baños, to the N.
Read allWed, 24 Jul 2002, 06:00
During 19-26 July, seismicity remained above background levels at Shiveluch. Individual earthquakes up to M 1.9, as well as a number of smaller earthquakes at depths of 0-6 km, were recorded. Other local seismic signals indicated that possible weak, ash-poor explosions rose to 1 km above the dome.
Read allWed, 24 Jul 2002, 06:00
Scientists were able to see Nyiragongo's crater on 27 July after 2 weeks without observations. They found that a very large white plume, which rose almost 3 km above the volcano, was being emitted from a small spatter cone inside the main crater. Lava was visible inside the spatter cone.
Read allWed, 24 Jul 2002, 06:00
An eruption began at Nyamuragira on the evening of 25 July that produced a cloud composed of steam, gas, and ash, 100- to 200-m-high lava fountains, and lava flows down the volcano's N and S flanks. According to the seismic record, the eruption began on the 25th at about 1310. National Park guards saw "smoke" rising above the volcano about an hour earlier.
Read allWed, 24 Jul 2002, 06:00
During 5-24 July, the level of volcanic activity fluctuated at Stromboli. Small explosions occasionally occurred at Northeast Crater, while fewer occurred at Southwest Crater. The central crater was inactive.
Read allWed, 24 Jul 2002, 06:00
Volcanic and seismic activity at Soufrière Hills during 19-26 July increased significantly in comparison to the previous week. A swarm of low-amplitude long-period earthquakes began on 19 July and increased in strength over the following 4 days. Observations of the lava dome on 21 July indicated that significant growth had recommenced, with the extrusion of a new lobe on the NE side of the summit region.
Read allWed, 24 Jul 2002, 06:00
When weather conditions were clear during 15-21 July, lava avalanches were observed traveling ~750 m from Semeru's crater rim E toward Besuk Kembar River. Explosions produced ash plumes reaching 300-500 m above the crater. Seismicity was dominated by 670 explosion earthquakes, while the number of other types of earthquakes decreased in comparison to the previous week.
Read allWed, 24 Jul 2002, 06:00
During 23-30 July, there were small-to-moderate emissions of steam, gas, and ash at Popocatépetl. Based on information from the Mexico City MWO, the Washington VAAC reported that on 26 July an ash cloud rose 5.5-6.7 km a.s.l.
Read allWed, 24 Jul 2002, 06:00
The Air Force Weather Agency reported that a low-level steam-and-ash cloud from Miyake-jima was visible on satellite imagery on 26 July at 0713 and on 27 July at 0606. Around this time a continuous plume was visible at a height of 2.4-3 km a.s.l.
Read allWed, 24 Jul 2002, 06:00
During 15-21 July, incandescent lava avalanches traveled predominately down Merapi's SW flank into the upstream portions of the Sat, Lamat, Senowo, and Bebeng rivers. The avalanches reached a maximum run-out distance of ~2.5 km. Seismicity was dominated by signals from 201 lava avalanches.
Read allWed, 24 Jul 2002, 06:00
Hundreds of spectators flocked to Kilauea to see the spectacular show of lava flowing into the sea at the end of easily accessible Chain of Craters Road. Surface lava flows were visible traveling down Pulama pali, Paliuli, and on the coastal flat. Generally, seismicity was at normal levels, except for the continued swarm of long-period earthquakes and tremor that has been ongoing since early June.
Read allWed, 24 Jul 2002, 06:00
During 20-26 July, seismicity was above background levels at Karymsky. Local, shallow seismic events occurred at a rate of ~10 events per hour. The character of the seismicity indicated that weak ash-and-gas explosions and gas blow-outs possibly occurred.
Read allWed, 24 Jul 2002, 06:00
According to VSI, on 15 July at 1355 an explosion at Karangetang's main crater produced an ash cloud to a height of 1.5 km above the crater. Ash fell to the N of the volcano. An accompanying lava avalanche traveled up to 1.5 km into Kahetang River Valley.
Read allWed, 24 Jul 2002, 06:00
During a visit to Etna on 26 July it was revealed that Strombolian activity had continued at Northeast Crater. Activity consisted of volcanic bombs being thrown beyond the rim of the crater. There was very little activity at Voragine and Southeast craters.
Read allWed, 17 Jul 2002, 06:00
At Tungurahua during 16-22 July, there were several emissions of steam, gas, and ash, periods of continuous tremor, and incandescence was occasionally visible. Several explosions produced ash clouds to a maximum height of 3 km. On the evening of the 21st, in addition to a 1-km-high volcanic cloud, observers noted lava fountains and incandescent blocks rolling down the NW flank.
Read allWed, 17 Jul 2002, 06:00
Surface observations from Kagoshima airport revealed that on 22 July an ash cloud from Sakura-jima rose to 2.1-2.4 km a.s.l. Ash was visible extending to the SW on satellite imagery. Ash was also observed on 23 July at an unknown altitude.
Read allWed, 17 Jul 2002, 06:00
Activity at Soufrière Hills increased slightly during 12-19 July, but remained at relatively low levels. Observations of the lava dome on 15 July suggested that dome growth had continued at a very slow rate on the SE side of the dome. The level of rockfall activity from this active lobe increased slightly on 15 July, with a small pyroclastic flow traveling down the Tar River Valley at 0800.
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