During an excursion to Colima on 17 March by personnel from the Universidad de Colima a new crater was observed that was assumed to have been formed during the 22 February 2001 eruption. The crater was ~190,000 m3 in volume, making it the largest crater to form at Colima since the 1960s. On 26 May scientists discovered that a new lava dome that was ~150,000 m3 in volume had formed in the crater.
On 29 May the Fukushima Local Meteorological Observatory reported that seismic activity increased slightly beneath Azuma during May. The Coordinating Committee for the Prediction of Volcanic Eruptions'seismic network detected 51 small-magnitude volcanic earthquakes during 21 and 22 May and 39 on 21 May (the most recorded in one day since November 1998). During March four low-frequency tremor events were recorded, while 40 were detected in April.
MVO reported that during 25 May-1 June volcanic activity remained at high levels. There was a significant increase in long-period earthquakes, although most were small. MVO personnel observed an area of new growth in the S sector of the lava dome.
Volcanic activity decreased following the 22 May eruption, therefore, on 30 May the Concern Color Code was further reduced from Orange to Yellow. During the week several small eruptions produced gas-and-steam plumes that rose up to 1.2 km above the old lava dome. Seismic activity decreased in comparison to the previous week, but remained above background levels.
CENAPRED reported that on 31 May at 2136 a moderate-sized eruption began with the most intense phase lasting ~1 minute. Incandescent material traveled 2-3 km down the NE flank of the volcano. According to the Mexico City MWO a steam-and-ash cloud was observed rising up to 7.6 km a.s.l. and drifting to the W.
During the week a large amount of high-frequency short-duration harmonic tremor occurred at Mayon. The tremor was associated with the intermittent descent of small lava avalanches and incandescent volcanic material down the Bonga Gully on the SE flank of the volcano. Moderate amounts of steam were observed rising from the summit crater where incandescence was occasionally observed.
During the beginning of the week lava flowed down Pulama pali and entered the ocean at two areas. By 3 June there were few surface flows with most of the lava traveling in lava tubes and entering the ocean sporadically. On 3 June a pause in volcanic activity may have begun at about 0900 with slow deflation (~2.6 microradians) occurring at the tiltmeter closest to HVO.
According to the Italy's Volcanoes website, volcanic activity was at similar levels as it has been during the previous few weeks. Lava continued to travel from a vent on the NNE flank of the Southeast Crater cone, and mild, discontinuous Strombolian activity continued at the Southeast Crater's summit vent. Scientists determined that the lava effusion rate was approximately 5-10 cubic meters per second, which is high for Etna.
Wed, 23 May 2001, 06:00
Based on information from the IG, the Washington VAAC reported that on 26 May at 2215 ash from an eruption of Tungurahua was observed at a height of ~7 km a.s.l. drifting to the NE. Extensive cloudiness in the area prohibited ash cloud detection on satellite imagery.
Read allWed, 23 May 2001, 06:00
The Washington VAAC reported that Masaya may have erupted on 23 May at ~1300. Ground observations from the capital city of Managua, 20 km NW of the volcano, indicated that there was a reduction in visibility to the SE of the city due to volcanic "smoke" and steam. The presence of the ash cloud could not be confirmed on satellite imagery due to thunderstorms in the area.
Read allWed, 23 May 2001, 06:00
MVO reported that during 18-25 May volcanic activity increased in comparison to the previous week. The main increase in activity occurred during 19 to 21 May when many large long-period and hybrid earthquakes were recorded. Low-level convective ash clouds generated during this increase in activity rose less than 2 km a.s.l.
Read allWed, 23 May 2001, 06:00
On 22 May at 0209 an explosive eruption produced a mushroom-shaped ash column that rose to a height of more than 10 km a.s.l. (preliminary reports stated ~20 km). The high-pressure system over N Kamchatka caused the plume to remain fairly stationary over the region as it spread out to cover an area of ~50,000 km2.
Read allWed, 23 May 2001, 06:00
Small-to-moderate sized exhalations occurred during the week. Based on information from the Mexico City MWO, the Washington VAAC reported that an eruption occurred on 26 May at 1122 that sent a steam-and-ash plume up to ~7 km a.s.l.
Read allWed, 23 May 2001, 06:00
During the week seismic activity was relatively low at Mayon and was associated with occasional rockfalls that descended to the SE down the Bonga Gully. In addition, moderate steaming occurred, incandescence was occasionally observed at the crater, and SO2 emission (up to 5,700 metric tons/day) was above the baseline value of 500 tons/day. On 28 May at 1036 the seismic network recorded a low-frequency volcanic earthquake that was inferred from seismic data to be associated with an ash puff.
Read allWed, 23 May 2001, 06:00
The tilt event that began on 20 May ended the following day and HVO reported that the precursory deflation, remarkably rapid inflation of 10-11 microradians in one hour, and then the slow relaxation of the summit presumably recorded a pulse of magma supplied to the summit reservoir complex. The pulse was then transferred to the Pu`u `O`o area where it is currently stored. Lava continued to flow into the ocean at the SE corner of the lava flow field.
Read allWed, 23 May 2001, 06:00
Based on information from the IG, the Washington VAAC reported that on 25 May at 1110 a steam-and-ash emission from Guagua Pichincha's summit rose up to ~8.5 km a.s.l. The cloud was not visible on satellite imagery.
Read allWed, 23 May 2001, 06:00
According to the Italy's Volcanoes website, through 25 May at Southeast Crater lava continued to flow from a small cone on its NNE flank and mild Strombolian activity continued at its summit vent. Volcanic activity had been relatively regular since a strong eruptive episode began on 9 May.
Read allWed, 23 May 2001, 06:00
Neither eruptive activity nor thermal anomalies have been observed at Cleveland during the previous 6 weeks.
Read allWed, 16 May 2001, 06:00
Volcanic activity increased slightly at Tungurahua during the week. On 15 May several small eruptions occurred, with the largest sending ash up to 3 km above the summit. Light ash fell in the towns of Cotaló and Bilbao.
Read allWed, 16 May 2001, 06:00
Due to the occurrence of several large explosions at Shiveluch, KVERT increased the Concern Color Code to Red on 21 May. An approximately 40-minute-long eruption began at 1556 on 19 May. An ash cloud rose to an altitude of 10 km a.s.l. and drifted to the NE.
Read allWed, 16 May 2001, 06:00
Volcanic activity increased at San Cristóbal on 17 May, accompanied by a relatively large amount of seismic tremor. Pulses of gas-and-ash emissions were observed rising up to 100 m above the rim of the volcano's crater. Light ash fell in the town of Santa Barbara, 14 km SW of the volcano.
Read allWed, 16 May 2001, 06:00
MVO reported that during 11-18 May volcanic activity increased, with about twice the number of rockfalls than the previous week. Most of the rockfalls were small and were observed to the SW of the summit, N of the town of Galway's. Growth of the lava dome was concentrated in the S sector of the volcano above White River.
Read allWed, 16 May 2001, 06:00
Small-to-moderate sized exhalations consisting mostly of gas and steam occurred at Popocatépetl during the week.
Read allWed, 16 May 2001, 06:00
AVO reported that the earthquake swarm centered near Okmok that was first detected on 11 May greatly diminished by 15 May.
Read allWed, 16 May 2001, 06:00
Based on information from the JMA, VRC reported that no ash clouds had been observed at Miyake-jima since the 19 March eruption. They also reported that steam plumes with abundant SO2 were continuously emitted from the summit caldera to 0.5-2 km above the caldera rim. Continuous SO2 emission released as much as 33,000 to 46,000 tons of SO2 per day.
Read allWed, 16 May 2001, 06:00
Elevated levels of volcanic activity continued at Mayon. Rockfalls were produced from fragments that were shed off of the summit lava dome. Seismic activity was relatively low.
Read allWed, 16 May 2001, 06:00
An article in the Jakarta Post stated that an eruption at Lokon that began at 2014 on 20 May deposited ash in a wide area around the volcano, including the provincial capital of Manado, approximately 20 km NE of the volcano. They reported that ash rose up to 900 m above the volcano and that the eruption was accompanied by tremor.
Read allWed, 16 May 2001, 06:00
Lava continued to flow down Pulama pali and was observed entering the sea at the SE corner of the lava flow field. On 20 May the largest tilt event to occur at Kilauea in more than 4 years took place. Beginning at 0500 the volcano's summit began to slowly deflate (~2 microradians) until about 1630 when it very abruptly began to inflate (~10 microradians).
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