According to a news report, a swarm of earthquakes occurred beneath Tristan da Cunha during the nights of 28 and 29 July. A scientist monitoring seismic activity from the Preparatory Commission for the Comprehensive Nuclear Test-Ban Treaty Organization, Vienna International Centre indicated that the main swarm lasted ~8 hours and occurred ~30 km below the volcano. After the swarm, there were a few individual earthquakes and then activity tapered off.
DVGHM stated that the pilot report of a plume emitted from Lewotolo on 25 June was false. Further investigation revealed that the emission was actually from Egon.
Satellite imagery showed a faint ash plume emitted from Galeras on 29 July around 0745. The height and direction of the plume was unknown.
Volcanic and seismic activity remained at relatively low levels at Tungurahua during 28 July to 2 August, with emissions of gas, steam, and small amounts of ash rising to ~500 m above the volcano.
Volcanic and seismic activity remained at low levels at Soufrière Hills during 23-30 July. The seismic network recorded two hybrid earthquakes and eight rockfalls. The sulfur-dioxide flux ranged between 175 and 300 metric tons per day, which is lower than the long-term eruption average of ~500 metric tons per day.
Low-level seismic tremor continued at Shishaldin during 22-30 July as it had for several months. On 24 July an AVO field crew observed vigorous steaming at the summit and what may have been ash deposits on the volcano's upper slopes. Shishaldin remained at Concern Color Code Yellow.
Seismicity was above background levels at Shiveluch during 22-30 July, with weak earthquakes occurring 0-5 km below the active lava dome. Gas-and-steam plumes rose to ~2.8 km a.s.l. on 28 and 29 July. Shiveluch remained at Concern Color Code Orange.
An episode of deformation consisting of deflation, inflation, then deflation began at Kilauea on the morning of 27 July. It was accompanied by increased surface activity at several places. During inflation, seismicity greatly increased below Kilauea's caldera.
Wed, 28 Jul 2004, 06:00
During 24-31 July, volcanic and seismic activity increased at Kerinci. An ash plume rose 100-600 m above the crater rim and drifted W. Ash was deposited up to 1 cm thick and as far away as 3 km from the crater.
Read allWed, 28 Jul 2004, 06:00
According to Universidad de Colima, during 27 July to 2 August an average of three ash-containing emissions occurred at Colima daily. The emissions did not rise higher than 3 km above the crater and mainly drifted W. The Washington VAAC reported that ash plumes were visible on satellite imagery during several days.
Read allWed, 28 Jul 2004, 06:00
During 26 July to 3 August, seismicity at Anatahan remained at very low levels. Interpretations of seismic data suggested that the frequent explosions during the previous week had decreased. Ash plumes probably did not rise higher than 6 km above the volcano.
Read allWed, 21 Jul 2004, 06:00
Small steam-and-ash emissions were accompanied by periods of volcanic tremor at Veniaminof during 16-23 July. On 22 July at 1229, an AVO field crew witnessed a small ash burst rise a few hundred meters above the summit of the intracaldera cone. This type of activity prevailed at Veniaminof during the previous 3 months.
Read allWed, 21 Jul 2004, 06:00
AVO raised the Concern Color Code at Spurr from Green to Yellow on 26 July after an increase in seismicity was recorded beneath the volcano's summit. Some earthquakes were interpreted to reflect the beginning stages of volcanic unrest. AVO noted that there were no indications that an eruption was imminent and that this type of seismicity can decline without leading to an eruption.
Read allWed, 21 Jul 2004, 06:00
A pilot reported that a thin plume emitted from Lewotolo was at a height of ~300 m above the summit on 25 July. Ash was not visible on satellite imagery.
Read allWed, 21 Jul 2004, 06:00
Based on information from IG, the Washington VAAC reported that an activity increase at Galeras during several days prior to 24 July consisted of emissions that rose ~600 m above the volcano's summit. Ash was not visible on satellite imagery. According to a news report, a wide area around the volcano was declared off limits to visitors.
Read allWed, 21 Jul 2004, 06:00
According to DVGHM, an eruption began at Egon on 25 July at 2240, consisting of loud rumbling sounds, a strong sulfur scent, and explosions that rose to 1-1.5 km above the summit. A thick, black plume drifted NNW from the volcano. Interpretations of seismic data revealed that the eruption lasted about 2.5 hours.
Read allWed, 21 Jul 2004, 06:00
During 25-26 July, volcanic and seismic activity were at low levels at Tungurahua. A few sporadic long-period earthquakes were related to small emissions from the volcano. Inclement weather prohibited observations of the emissions.
Read allWed, 21 Jul 2004, 06:00
Volcanic and seismic activity at Soufrière Hills remained at low levels during 16-23 July. The seismic network recorded seven hybrid earthquakes and seven rockfalls. No long-period events or volcano-tectonic earthquakes were recorded.
Read allWed, 21 Jul 2004, 06:00
During 21-27 July, weak-to-moderate explosions from Santa María's Santiaguito lava-dome complex produced plumes to heights ~700 m above the volcano. During the report period, several avalanches of volcanic material traveled SW down Caliente cone.
Read allWed, 21 Jul 2004, 06:00
According to the Toulouse VAAC, an eruption began at Nyiragongo sometime before 0700 on 27 July. Satellite imagery showed that the plume produced from the eruption rose to between 3.6 and 4.9 km a.s.l.
Read allWed, 21 Jul 2004, 06:00
According to a news article, during the week of 18 July emissions from Mayon deposited ash on two villages near the volcano. Reportedly, a PHIVOLCS scientist stated that the explosions may have occurred due to water contacting hot rocks.
Read allWed, 21 Jul 2004, 06:00
Several surface lava flows were visible at Kilauea during 22-26 July, and all vents in the crater of Pu`u `O`o were incandescent. Seismicity was weak beneath Kilauea's summit and tremor at Pu`u `O`o was at moderate-to-high levels. During 22-25 July, deflation occurred at Pu`u `O`o.
Read allWed, 21 Jul 2004, 06:00
A series of strong explosions at Fuego on 21 July during 0630-0950 produced ash plumes to a height of ~2 km above the volcano. Plumes traveled W, SW, and S, depositing ash in several villages near the volcano. Small incandescent avalanches of volcanic material traveled to the mouths of several ravines.
Read allWed, 21 Jul 2004, 06:00
Seismicity at Anatahan approached the highest levels of the year on 23 July. That day, Strombolian explosions frequently threw mostly coarse material up to hundreds of meters at intervals of tens of seconds to minutes. On 26 July, there were nearly continuous ash-and-gas emissions.
Read allWed, 14 Jul 2004, 06:00
Short intervals of low-level volcanic tremor continued intermittently at Veniaminof during 9-16 July. According to AVO, the episodes of tremor correlated well with small ash-and-steam emissions that may have reached as high as 3.6 km a.s.l. Veniaminof remained at Concern Color Code Yellow.
Read allWed, 14 Jul 2004, 06:00
DVGHM reported that seismic and volcanic activity were at heightened levels on 17 July at Papandayan. The number of volcanic earthquakes increased on 13 July from 1-3 per day to 7-9, then further increased to 57 earthquakes on 16 July. The temperature at Baru crater I increased from 84 to 88.5 °C, and the temperature of Baru crater II rose from 89 to 102 °C.
Read allWed, 14 Jul 2004, 06:00
In July there was an increase in the number of gas-and-steam emissions from the crater of Anak Krakatau. In addition, the number of volcanic earthquakes increased from 1-4 per day before 5 July, to ~57 per day, then dropped to 2-17 earthquakes per day by mid-July. The Alert Level at Krakatau was raised from 1 to 2 (on a scale of 1-4).
Read allWed, 14 Jul 2004, 06:00
Volcanic and seismic activity at Tungurahua remained at moderate levels. Tremor was associated with emissions of steam, gas, and ash.
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