Volcanic and seismic activity remained at low levels at Soufrière Hills during 20-27 February. A period of low-level tremor began on 21 February around 0600 that continued for ~36 hours and consisted of many small long-period earthquakes. On 24 February around 0915 mudflows swept down the Belham valley (NW of the volcano) for ~40 minutes during intense rainfall.
During 20-27 February, seismicity was above background levels at Shiveluch, with a large number of weak shallow earthquakes occurring at depths of 0-5 km beneath the active lava dome. Based on interpretations of seismic data, on 23 February an ash-and-gas explosion produced a plume to ~5 km a.s.l. Gas-and-steam plumes were seen rising to ~4 km a.s.l.
During 25 February to 2 March, weak-to-moderate explosions continued at Santa Maria's Santiaguito lava-dome complex. Ash-and-gas plumes rose to ~1.4 km above the crater, and ash fell in the mountainous region around the volcano. Weak-to-moderate avalanches of volcanic material traveled from lava-flow fronts.
During 16-22 February, the average number of long-period earthquakes (4.1) and volcano-tectonic earthquakes (17) at Reventador nearly doubled in comparison to the previous week. Satellite imagery on 21 February showed a plume from Reventador drifting NNE.
Seismicity at Kliuchevskoi was above background levels during 20-27 February, with ~160 M 1.25-1.75 earthquakes and 12 M 1.25-2.25 earthquakes occurring at depths of 3-7 km beneath the volcano. Gas-and-steam plumes rose to ~700 m above the volcano. Kliuchevskoi remained at Concern Color Code Orange.
According to a news report, on 1 March four M 1.75-3.75 earthquakes were recorded at Kizimen by the Kamchatkan Experimental Methodical Seismological Department. KVERT scientists believe these earthquakes were probably tectonic. No signs of increased volcanic activity were visible on satellite imagery.
During 26 February to 1 March at Kilauea, incandescence revealed surface lava flows in the southern part of the rootless shield complex (an area ~0.5 km SW of Pu`u `O`o) and in Pu`u `O`o's crater. Very weak background tremor continued at Kilauea's summit, and volcanic tremor at Pu`u `O`o was at moderate levels. There were periods of inflation and deflation at Pu`u `O`o and Kilauea's summit.
Seismicity remained above background levels at Karymsky during 20-27 February, with 30-100 shallow earthquakes during the week. Based on interpretations of seismic data, several ash explosions during 19-25 may have produced ash plumes to a maximum height of 6.5 km a.s.l. On 20 February an ash plume was seen rising to ~3.5 km a.s.l.
Wed, 25 Feb 2004, 06:00
Activity at Guagua Pichincha remained at low levels during 16-22 February, with only gas plumes rising from fumaroles. There was a slight increase in volcano-tectonic earthquakes. During 18-20 February, harmonic tremor was recorded.
Read allWed, 25 Feb 2004, 06:00
During 25 February to 2 March weak-to-moderate explosions continued at Fuego, producing plumes to ~1.7 km above the crater. Avalanches of volcanic material traveled down several ravines, including Trinidad, Ceniza, Santa Teresa, and Taniluyá (to the W). Explosions on 28 February deposited small amounts of fine ash in the village of Sangre de Cristo, and explosions on 29 February deposited ash W and SW of the volcano in the villages of Yepocapa and La Cruz.
Read allWed, 25 Feb 2004, 06:00
During 25-27 February, the Darwin VAAC reported thin ash plumes from Dukono that were visible on satellite imagery extending a maximum distance of 160 km towards the E at a height of ~3 km a.s.l.
Read allWed, 25 Feb 2004, 06:00
According to the Universidad de Colima, during 17-20 February volcanic activity slightly decreased at Colima in comparison to the previous week. About three explosions occurred daily, producing ash columns to 2-3 km above the crater. Most of the columns drifted ENE and NE, depositing ash on the volcano's flanks.
Read allWed, 18 Feb 2004, 06:00
During the week of 15 February, AVO received several reports of small ash clouds rising "several hundred feet" above the intracaldera cinder-and-spatter cone of Veniaminof. Residents of Perryville reported a "black puff" of ash on 16 February followed by strong steaming, and a pilot reported a small black ash cloud on 19 February. Satellite imagery on 19 February at 1410 showed a small, dark trail on the snow leading away from the intracaldera cone that was likely a very localized ash deposit.
Read allWed, 18 Feb 2004, 06:00
During 19-23 February, emissions of steam, gas, and ash continued at Tungurahua. On the afternoon of 19 February ash fell in the towns of Puela (~8 km SW of the volcano) and Pillate (~8 km W of the volcano). An explosion on 22 February at 2355 produced an avalanche of incandescent volcanic blocks that traveled ~1 km from the summit.
Read allWed, 18 Feb 2004, 06:00
During 13-20 February, volcanic and seismic activity remained low at Soufrière Hills. The seismic network recorded one rockfall and three hybrid earthquakes. Sulfur-dioxide flux was at moderate levels, reaching between 350 and 650 metric tons per day.
Read allWed, 18 Feb 2004, 06:00
During 13-20 February, seismicity was slightly above background levels at Shiveluch. A large number of weak, shallow earthquakes was recorded daily at depths of 0-5 km beneath the active lava dome. Spasmodic tremor was recorded the entire week.
Read allWed, 18 Feb 2004, 06:00
On 19 February moderate explosions continued at Santa María's Santiaguito lava-dome complex. Plumes rose 0.7-1 km above the volcano and mainly drifted SSW as fine ash fell in the mountainous region around the volcano. On 23 February avalanches of lava blocks and derived ash traveled SW down the lava dome.
Read allWed, 18 Feb 2004, 06:00
Relatively high amounts of gas discharge continued at Miyake-jima through 22 February. The sulfur-dioxide emission rate has been nearly constant (4,000-9,000 tons per day) since October 2002. Due to volcanic unrest, residents of the volcanic island have been evacuated since September 2000.
Read allWed, 18 Feb 2004, 06:00
During 13-20 February seismicity was above background levels at Kliuchevskoi, with 135 earthquakes of M 1.25-1.7 and 1-6 earthquakes up to M 1.85 occurring daily at depths of 3-6 km beneath the volcano. Gas-and-steam plumes rose to ~1 km above the volcano. Kliuchevskoi remained at Concern Color Code Orange.
Read allWed, 18 Feb 2004, 06:00
During 19-23 February, lava mainly erupted from the S side of Kilauea's Pu`u `O`o crater. A large deflation event on 21 February during 0711 to 1413 amounted to 10.9 microradians of deformation. Weak background tremor continued at Kilauea's summit along with a few long-period earthquakes.
Read allWed, 18 Feb 2004, 06:00
During 12-16 February, seismicity was above background levels at Karymsky. No seismic data were recorded during 17-18 February. Based on interpretations of seismic data, during 12-14 February five ash-and-gas explosions produced plumes that rose 4-4.5 km a.s.l., and on 15 February explosions produced two plumes to ~3 km a.s.l.
Read allWed, 18 Feb 2004, 06:00
During 18-19 February, several moderate-to-strong explosions at Fuego produced ash plumes to .8-1.5 km above the crater. The explosions also produced landslides of incandescent volcanic material that traveled down several ravines: Seca (to the SW), Taniluyá (to the W), Trinidad, Ceniza, and sometimes towards Las Lajas-El Jute. Small amounts of fine ash were deposited to the W in the village of Sangre de Cristo.
Read allWed, 18 Feb 2004, 06:00
The Darwin VAAC reported that during 20-22 February thin ash plumes from Dukono were visible on satellite imagery, extending predominately E to a maximum distance of 90 km.
Read allWed, 18 Feb 2004, 06:00
According to the Washington VAAC, during 17-22 February there were several steam-and-ash emissions from Colima, with the highest rising plumes reaching ~6 km a.s.l.
Read allWed, 18 Feb 2004, 06:00
On 29 January a swarm of ~148 small volcano-tectonic earthquakes occurred at Cayambe. By 1 February seismicity had decreased, reaching "normal" base levels. IG reported that the swarm may have represented an increase in the internal pressure of the volcano due to the arrival of fluid, possibly magma.
Read allWed, 18 Feb 2004, 06:00
On 19 and 20 February, explosions at Sakura-jima produced ash clouds that rose to unknown heights. No ash was visible on satellite imagery.
Read allWed, 11 Feb 2004, 06:00
During 11-16 February, small-to-moderate explosions at Tungurahua produced steam, gas, and ash plumes to ~1 km above the volcano. On 11 February an avalanche of incandescent volcanic blocks traveled ~1 km down the volcano's flank.
Read allWed, 11 Feb 2004, 06:00
Volcanic and seismic activity at Soufrière Hills remained at low levels during 6-13 February. The seismic network recorded one volcano-tectonic earthquake and three hybrid earthquakes. Sulfur-dioxide flux was low and relatively constant at 350-450 metric tons per day.
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