During 24 September to 1 October, low-level tremor and intermittent small tremor bursts may have occurred at Veniominof, but high winds in the area made analysis of seismic records inconclusive. The winds were strong enough to produce an overshadowing effect on seismic records that could hide evidence of low-level tremor. If the tremor episodes continued, they likely represented low-level ash-and-steam emissions similar to those observed over the previous 4 months.
Shortly before noon on 1 October, Mount St. Helens emitted a plume of steam and minor ash from an area of new crevasses that had opened in a portion of the crater glacier between the headwall of the 1980 crater and the lava dome. This marked the first eruption from Mount St.
Wed, 29 Sep 2004, 06:00
Based on information from DVGHM, the Darwin VAAC reported that an eruption at Rinjani on 1 October at 0530 produced a plume to ~600 m above the volcano's summit. No ash was visible on satellite imagery. The volcano was at Aviation Color Code Orange.
Read allWed, 29 Sep 2004, 06:00
During 29 September to 5 October seismic and volcanic activity at Tungurahua were at relatively low levels, with the occurrence of occasional small explosions of gas, steam, and ash and some long-period earthquakes.
Read allWed, 29 Sep 2004, 06:00
Volcanic and seismic activity at Soufrière Hills during 24 September to 1 October remained slightly elevated, as has been the case for several weeks. The seismic network recorded three rockfalls, one long-period earthquake, and eight hybrid earthquakes. Sulfur-dioxide flux ranged between 200 and 540 metric tons per day, with a weekly average of 340 metric tons.
Read allWed, 29 Sep 2004, 06:00
During 30 September to 4 October moderate explosions at Santa María's Santiaguito lava-dome complex produced ash-and-gas plumes to a maximum height of 1 km above the volcano. Some explosions were accompanied by avalanches of volcanic material down the S side of Caliente dome. Explosions on 4 October produced small 3-minute-long pyroclastic flows to the SW.
Read allWed, 29 Sep 2004, 06:00
The main recent eruption phase at Piton de la Fournaise began on 13 August 2004 and stopped on 2 September. It was followed by two minor phases from the main vent on the volcano's E flank; these, in turn, ceased on 3 October around 0300.
Read allWed, 29 Sep 2004, 06:00
During 30 September to 5 October, patches of incandescence were visible at the PKK lava flow on the Pulama pali scarp and all vents in the crater of Pu`u `O`o were incandescent. During the report period, seismicity was weak at Kilauea's summit, with essentially no tremor recorded. Tremor was moderate at Pu`u `O`o.
Read allWed, 29 Sep 2004, 06:00
During 30 September to 4 October several explosions occurred at Fuego, producing ash plumes to a maximum height of 2 km above the volcano. On 30 September, lava avalanches traveled towards Santa Teresa and Taniluya ravines. On 1 October, incandescent lava bombs were hurled ~100 m above the volcano.
Read allWed, 29 Sep 2004, 06:00
A new growing lava dome was sighted in Colima's summit crater on 28 September, following three days of vigorous fumarolic emissions. Starting on 30 September, block-and-ash flows moved down the volcano's W, WNW, and N flanks. Blocks of lava began to travel down the volcano's N and WNW flanks around 1 October, reaching lengths of ~300 m on the N flanks and ~100 m on the WNW.
Read allWed, 22 Sep 2004, 06:00
Low-level tremor and intermittent tremor bursts continued at Veniaminof during 17-24 September. Tremor episodes likely represented low-level ash-and-steam emissions similar to those observed over the previous 4 months, although cloudy conditions obscured views of the volcano in web camera and satellite imagery. Veniaminof remained at Concern Color Code Yellow.
Read allWed, 22 Sep 2004, 06:00
CVO issued a Notice of Volcanic Unrest for Mount St. Helens on 26 September. They reported that increased activity started when a swarm of very small, shallow earthquakes (less than M 1) began on the morning of 23 September.
Read allWed, 22 Sep 2004, 06:00
During 21-27 September, relatively low-level activity continued at Tungurahua. There were emissions of gas, steam, and ash. In addition, sporadic explosions produced plumes to a maximum height of 3 km above the volcano.
Read allWed, 22 Sep 2004, 06:00
Elevated seismicity continued at Spurr during 17-24 September, with an average of ten earthquakes occurring within 30 km of the summit daily. The combined output of carbon dioxide from one vent at Crater Peak and one at Spurr was approximately 2,300 tons on 15 September, an increase from the approximately 760 tons/day measured during 7-8 August. AVO reported that the gray color of the lake at the bottom of the ice cauldron is typical of crater lakes containing dissolved sulfur dioxide.
Read allWed, 22 Sep 2004, 06:00
Volcanic and seismic activity at Soufrière Hills remained slightly elevated throughout 17-24 September. The seismic network recorded two rockfalls, two long-period earthquakes, and eight hybrid earthquakes. The sulfur-dioxide flux averaged 312 metric tons per day, reaching a maximum of 454 metric tons on 18 September.
Read allWed, 22 Sep 2004, 06:00
Seismicity was above background levels at Shiveluch during 23 September to 1 October, with 26 strong shallow earthquakes up to M 2.3 recorded during 23-29 September. Several explosions were seen that produced ash plumes to a maximum height of 4.5 km a.s.l., while interpretations of seismic data suggested that plumes rose to 6.5 km a.s.l. [Correction: According to interpretations of seismic data there were ~20 ash plumes at heights between 4 and 6.5 km a.s.l.
Read allWed, 22 Sep 2004, 06:00
Moderate explosions occurred at Santa Maria's Santiaguito lava-dome complex during 21-27 September. On the 27th, several avalanches of volcanic material from active lava-flow fronts traveled SW.
Read allWed, 22 Sep 2004, 06:00
The Toulouse VAAC reported that on 28 September a thin, narrow plume emitted from Nyiragongo was visible on satellite imagery.
Read allWed, 22 Sep 2004, 06:00
No changes were noted by HVO at Mauna Loa through 27 September. Since early July 2004, an increasing number of earthquakes had been recorded from beneath Mauna Loa. From week to week the numbers fluctuated but remained well above the earlier established norm.
Read allWed, 22 Sep 2004, 06:00
According to the Darwin VAAC, a pilot reported seeing a plume from Manam on 22 September at 1345 drifting W at a height of ~3 km a.s.l. Ash was not visible on satellite imagery.
Read allWed, 22 Sep 2004, 06:00
During 22-27 September, all vents in Kilauea's Pu`u `O`o cone were incandescent. After several days of absence, lava was again visible on the Pulama pali fault scarp beginning on the 23rd. The lava was at the tip of the western branch of the PKK flow.
Read allWed, 22 Sep 2004, 06:00
Based on information from JMA, the Tokyo VAAC reported that an eruption at Kikai on 25 September at 0937 produced a plume to a height of ~1.5 km a.s.l. that extended W.
Read allWed, 22 Sep 2004, 06:00
A pilot reported to the Darwin VAAC that an ash cloud emitted from Kerinci was visible on 27 September at 0813 drifting W at a height of ~6 km a.s.l. Ash was not visible on satellite imagery.
Read allWed, 22 Sep 2004, 06:00
During 23-27 September, tremor associated with ash-and-gas emissions was recorded at Galeras. On the 23rd, ash deposits were seen on the upper portions of the volcano's N flank. By the 27th the amount of tremor had decreased significantly, which may have coincided with a decrease in ash emissions.
Read allWed, 22 Sep 2004, 06:00
Weak explosions at Fuego on 21 September produced white plumes to ~200 m above the volcano. During 25-26 September, several moderate explosions emitted incandescent lava bombs to heights of ~150 m and plumes to 600-900 m above the volcano. The explosions were accompanied by avalanches of volcanic material that traveled W to the head of Santa Teresa Ravine.
Read allWed, 22 Sep 2004, 06:00
On 26 September, satellite imagery showed a plume erupted from Dukono extending WNW at a height of ~3 km a.s.l.
Read allWed, 22 Sep 2004, 06:00
Low-intensity volcanic activity continued at Colima through 27 September, with about two ash explosions occurring per day. The plumes produced from these explosions did not rise more than 2 km above the volcano and predominately drifted W.
Read allWed, 22 Sep 2004, 06:00
Based on information from JMA, the Tokyo VAAC reported that eruptions at Asama during 23-25 September produced plumes to unknown heights.
Read allWed, 15 Sep 2004, 06:00
Low-level seismic tremor and intermittent tremor bursts continue to be recorded at Veniaminof. Tremor episodes likely represent low-level ash and steam emissions similar to those observed over the past four months. Minor emissions of volcanic ash and steam were occasionally observed using web camera images during times of clear weather.
Read allWed, 15 Sep 2004, 06:00
According to JMA, as reported by the news media, Asama erupted almost continuously for a third straight day on 16 September, causing more than 1,000 earthquakes. Incandescent fragments were ejected ~300 m from the summit and ash columns rose ~1,200 m above the crater. Late that night winds carried ash as far as central Tokyo.
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