INGEMMET reported that on 18 April, explosions from Ubinas produced gas and ash plumes to altitudes of 5.9-7.7 km (19,400-25,300 ft) a.s.l. Plumes drifted SW. Based on significant meteorological (SIGMET) notices, satellite imagery, and pilot reports, the Buenos Aires VAAC reported that ash plumes rose to altitudes of 5.5-7 km (18,000-28,000 ft) a.s.l. on 17, 18, 22, and 24 April. Plumes drifted NW, SW, and SE.

IG reported that during 17-18 April, Strombolian activity from Tungurahua was observed; incandescent material was ejected about 500 m above the summit and blocks descended down the flanks. Lahars carring large blocks NW down the Mandur gorge caused a road closing on 19 April. During 17-24 April, ash plumes rose to altitudes of 5.5-9 km (18,000-29,500 ft) a.s.l. and drifted W and N. Ashfall was reported from areas mainly to the N, NW, W, and SW during 17, 19, 21-22, and 24 April. On 23 April, lahars were observed in several gorges to the NW. Clouds occasionally inhibited views of the summit during the reporting period.

Data from deformation-monitoring instruments and observations from a remote camera showed that during 18-24 April lava-dome growth at Mount St. Helens continued. Seismicity persisted at low levels, punctuated by M 1.5-2.5, and occasionally larger, earthquakes. In some instances, clouds inhibited visual observations.

During 13-20 April, visual observations suggested that lava-dome growth at Soufrière Hills continued at a reduced rate. Material originating from the lava dome’s growing E-facing shear lobe was shed down the Tar River Valley. Heavy rains resulted in lahars in several drainages 16-17 April. During 18-20 April, a gas plume drifted N and NE and a bluish haze containing sulfur dioxide was observed flowing down the N flanks due to light winds coming from the S.

Background levels during 13-20 April. Based on seismic interpretation, observation, and video data, ash-and-steam plumes possibly rose to altitudes of 5.5-6.5 km (18,000-21,300 ft) a.s.l. throughout the reporting period. Plumes were seen on satellite imagery drifting E, SE, and S and a thermal anomaly was present. Base on pilot reports, satellite imagery, KEMSD, and observations from the Petropavlovsk-Kamchatsky Flight Information Region (FIR), the Tokyo VAAC reported that ash plumes rose to altitudes of 4.6-6.1 km (15,000-20,000 ft) a.s.l. during 18-22 April. They drifted E. The Level of Concern Color Code remained at Orange

INSIVUMEH reported that explosions from Santa María's Santiaguito lava dome complex on 20 and 23 April occasionally produced ash plumes that rose to altitudes of 5.3 km (17,400 ft) a.s.l. The plumes drifted SW and ashfall was reported from areas up to 9 km to the SW. On 23 April, lava flows on the SW and NE flanks of Caliente dome produced small landslides composed of blocks.

On 18, 20, and 23 April, steam-and-gas emissions from Reventador hung near the summit. On 18 April, a plume was seen drifting NW on satellite imagery. On 20 April, a bluish haze of gases was observed. Clouds occasionally inhibited views of the summit during 18-24 April.

During 13-20 April, Strombolian activity occurred at Kliuchevskoi, based on observations and video data. Seismic activity continued above background levels and a thermal anomaly in the crater was detected on satellite imagery. Fumarolic activity intensified during 15 and 17-18 April. Gas-and-steam plumes possibly containing small amounts of ash rose to altitudes of 6.3-7.2 km (20,700-23,600 ft) a.s.l. during 15 and 17-18 April and drifted in multiple directions. Based on pilot reports, satellite imagery, and observations in the Petropavlovsk-Kamchatsky Flight Information Region (FIR), the Tokyo VAAC reported several E-drifting ash plumes. They rose to altitudes of 5.2 (17,000 ft) a.s.l. and 8.8 km (29,000 ft) on 18 and 22 April, respectively. On 24 April, KVERT reported mudflows and phreatic activity at lava flow fronts on the NW flank. Resultant ash plumes rose from the lava flow fronts to an altitude of 3.5 km (11,500 ft) a.s.l. The Level of Concern Color Code remained at Orange

During 18-24 April, lava from Kilauea continued to flow SE across a lava delta into the ocean at the Kamokuna entry, but lava was not seen entering the ocean at East Lae'apuki. Incandescence was intermittently visible from several breakouts on the Pulama pali and from several vents in the Pu'u 'O'o crater. Earthquake activity was scattered at the summit and S-flank areas. Tremor remained at moderate levels.

Seismic activity at Karymsky was above background levels during 13-20 April. Ash plumes from explosions occurred during 13-20 April and may have reached altitudes of 4 km (13,000 ft) a.s.l. during 15-16 April and drifted E. Based on visual observation, a gas-and-steam plume rose to an altitude of 2.5 km (8,200 ft) a.s.l. on 19 April and a possible new lava flow was seen on the SW flank. A thermal anomaly in the crater was detected on satellite imagery during 14-16 April. Based on pilot reports, satellite imagery, and observations in the Petropavlovsk-Kamchatsky Flight Information Region (FIR), the Tokyo VAAC reported that an ash plume rose to an altitude of 7.6 (25,000 ft) a.s.l. and drifted SE. The Level of Concern Color Code remained at Orange

INSIVUMEH reported that on 20 and 23 April, Strombolian activity was observed at Fuego; incandescent material was ejected about 50-75 m above the summit and blocks descended 300 m down the S and W flanks. On 20 April, sounds resembling locomotives accompanied the eruption, and lava overflowed the crater on the S flank and traveled 100 m. The Washington VAAC reported that an intense hotspot seen on satellite imagery on 21 April was likely caused by a lava flow to the SW, according to information from INSIVUMEH. A plume drifting SW was also visible on satellite imagery and may have been a result of fires started by lava flows; the plume may have also contained light ash and gas. On 23 April, INSIVUMEH reported that pyroclastic flows and incandescent avalanches traveled down SE and SW ravines. Ash explosions caused light ashfall in areas S of the volcano and fumarolic and gas plumes rose to an altitude of 4 km (13,000 ft) a.s.l.

KVERT reported that bursts of volcanic bombs from Chikurachki were observed by hunters on 15 April. Ash plumes were seen on satellite imagery drifting SE on 14 April and WNW during 15-16 April. Ash plumes rose to altitudes of 3.8 km (12,500 ft) a.s.l. and drifted N on 18 April. The Level of Concern Color Code remained at Orange.

Based on satellite imagery and aerial observation on 15 April, Anatahan’s crater lake emitted diffuse steam-and-gas plumes. Tremor increased and remained elevated on 20 April.

OVPDLF reported that the eruption of Piton de la Fournaise from the S-part of the Grand Brûlé continued during 18-24 April. Tremor in this area remained very low throughout the reporting period. On 22 April, a large plume was visible from where lava flows met the sea. On 23 April, abundant lava flows in Grand Brûlé traveled in lava tubes. A collapsed lava-tube ceiling resulted in the formation of a hornito.

Based on satellite imagery, the Washington VAAC reported that an ash eruption from Nevado del Huila on 18 April produced a plume that drifted SW and dissipated. On 22 April, INGEOMINAS reported that during aerial observations, fumarolic activity was observed from a fissure first noted on 19 February. The fissure was approximately 2.3 km long and 0.2 km wide. A resultant plume rose to an altitude of 10.4 km (34,100 ft) a.s.l. Another fissure, extending about 2 km from the SW to the NE sector of Pico Central, also produced fumarolic emissions. Mudflows in the Páez and Símbola rivers originating on Pico Central primarily swept through the Oso ravine on the E flank and Bellavista ravine on the W flank.According to news articles, the eruption during 17-18 April caused damage to houses and destroyed 19 bridges along the Páez and Símbola rivers. Several kilometers of a highway, used to transport goods and medicines to the population, were also destroyed. INGEOMINAS noted that there were no reported deaths or injuries as a result of the eruption.

Based on pilot reports and satellite imagery, the Wellington VAAC reported that ash plumes from Lopevi rose to altitudes of 2.4-4.6 km (8,000-15,000 ft) a.s.l. during 21-24 April. Plumes drifted E on 21 April.

INETER reported that explosions in the crater of Concepción on 22 April produced ash-and-gas plumes that drifted WSW.

Weakly alimented lava flows continue to run from the 500 m vent at the volcano.

INETER reported that explosions in the crater of Concepción on 8 April produced an ash-and-gas plume that rose to an altitude of 2.7 km (8,900ft) a.s.l. and drifted W.

On 18 of April, Nevado del Huila had a moderately strong ash eruption causing ash fall and lahars on its flancs due to melted snow and ice water. About 8000 people have been evacuated. After the explosion, seismic activity at the volcano has decreased again.

Both tremor and the lava output have been strongly decreasing over the past days at Fournaise volcano, suggesting a possible end of the eruption in the near future.

Lava flows on Hawaii - new photos from Nov 06-April 07

New photos from lava flows on Kilauea volcano on Hawaii, taken during the past months on our tours, have been posted online.

On 12 April at 15h05 local time, a second larger collapse took place at the summit crater Dolomieu. The new impressive pit crater has cut the area next to the pit crater Bory, which is now no longer supported and itself at risk of collapsing into Dolomieu.

On 11 April, the eruption resumed at Piton de la Fournaise: new weak lava fountains appeared again at the fissure vent at around 500 m elevation, the same that opened on 2nd of April.

Another brief, but intense eruption occured at Etna today, similar to the one on 29 March: lava fountains erupted from the SE crater and two lava flows emerged from the vent at the base of the SE cone at 3050 m, flowing into Valle del Bove. The eruption lasted for 5 hrs and the most advanced lava flow front reached 1900 m elevation in the Valle del Bove. 

The eruption at Fournaise volcano seems to come to an end.
On late 9 April, no surface lava flows were visible and all lava from the vent is flowing in lava tunnels on the slope of the Grande Brulée. At 14h00 local time on 10 April, lava fountains ended and lava emission at the vents stopped, triggering scientist to announce the end of the eruption. In the evening, only small residual lava flows were observed, probably relating to drainage of the feeding system and the lava channels and tubes.
During the past days, further smaller collapses have continued to affect the walls of the summit crater. The area surrounding the summit is covered with a deposit of 5-7 cm of ash.
A large number of dead deep-water fish have been found floating on the heated water surrounding the lava sea entry. More than 30 different species have been counted by scientist, some of which seem to be unknown.

The eruption at Piton de la Fournaise volcano continues and eruptive activity, lava fountains and lava flow emissions from the fissure vent at 600-500 m elevation, increases.

After the collapse of the summit crater, the eruption seems to have calmed down a bit compared to the extreme levels ovbserved during the past days. Lva fountains of 50-100 m height continue to feed a cluster of lava flows that have cut the national road on a length of 1 km and are creating new land at a spectacular, growing sea entry delta. Steam loaded with acid gasses and Pele's hair created at the sea entry continue to create health problems in much of the nearby, inhabited coastal areas.

After 3 montsh of relative quiet, Bulusan had another (probably phreatic or phreatomagmatic) eruption today, Easter Sunday. The eruption lasted for 20 minutes and produced an ash colum that rose 2,5 km into the sky.

As had been forecasted by scientists, the summit of Piton de la Fournaise volcano has collapsed today (7 April). Practically all of the interior of Dolomieu crater has collapsed into a new pit crater with vertical walls and 300 m depth, with an estimated collapse volume of 50 million cubic meters. 
The activity has been accompanied by strong earthquakes beneath the summit and produced dense ash clouds. At present, seismic activity continues in the area below the summit; further collapse could happen in the near future.
The series of events at Piton de la Fournaise marks one of the largest pit craters to be formed ever observed in historic time on a volcano.
In the meanwhile, lava emission at extremely high rates from the eruptive fissure continues.

The debit of the lava flow has reached unusually high levels, as a report from the volcano observatory communicates: "...probably much higher than 100 m3 per second, a value which has not been observed at Réunion Island within the last 20 or 30 years. The national road is cut over more than 1 km."

"High values of sometimes over 300 micrograms per m3 of SO2 had been measured by the Observatoire Réunionnais de l’Air (ORA) in the western and northern part of the island.
Dust and Pele’s hair from the eruption site were observed even at 10 to 20 km away and small, mm sized grains of basalt, formed by the lava flow into the sea and transported by the steam plume (generated at the lava flow entry into the sea) were observed within 5 km of the site.

Based on pilot reports, the Buenos Aires VAAC reported that an ash cloud from Ubinas rose to 5.5-6.1 km (18,000-20,000 ft) a.s.l. on 30 March and drifted E. According to a news article, local residents observed rockfalls and reported ashfall. A scientist from the Geological, Mining, and Metallurgic Institute (INGEMMET) reported that the eruption was the largest in a two-week period characterized by an increased rate of explosions. A diffuse ash plume was visible on satellite imagery on 3 April drifting NE.

Data from deformation-monitoring instruments and observations from a remote camera showed that during 28 March-3 April, lava-dome growth at Mount St. Helens continued. Seismicity persisted at low levels, punctuated by M 1.5-2.5 and occasionally larger earthquakes. On 3 April, a GPS unit on an active spine showed W-ward movement at a rate of about 30 cm/day.

Over the past days, lava-dome growth at Soufrière Hills was reduced or possibly paused. Small, intermittent pyroclastic flows occurred in the Tar River Valley.

The first explosive event at Shiveluch on 29 March produced an ash plume rising to an estimated altitude of 9.8 km (32,000 ft) a.s.l. and drifted NE. Based on reports from the Yelizovo Meteorological Watch Office and satellite imagery, the Tokyo VAAC reported that the plume reached an altitude of 11.9 km (39,000 ft) a.s.l. The next day, an explosive event that lasted about 6 minutes produced a plume to altitudes of 10.1-12.2 km (33,000-40,000 ft) a.s.l., based on estimates from AVO, Tokyo VAAC, and the Kamchatkan Branch of Geophysical Services. The plume drifted NE.
According to a news article, a mudflow covered an approximately 900-m-long section of road, about 20 km from Shiveluch on 31 March.

Santa María's Santiaguito lava dome is in an elevated stage of activity. Explosions produced ash plumes that rose to an altitude of 5 km (16,400 ft) a.s.l. on 29 March. Ashfall was reported near the Observatory Vulcanológico de Santiaguito (OVSAN), about 5 km S. On 2 April, INSIVUMEH reported that ash plumes rose to 4.4 km (14,400 ft) a.s.l. and drifted SW.

Strombolian activity continues at Tavurvur volcano, the active cone inside the Rabaul caldera. Bombs are ejected to 100 m above the crater rim and ash plumes rise to 1-3 km.

Occasional ash eruptions continue at Popocatepetl volcano. On 1st of April, Popo produced an eruption plume that rose to an altitude of 7.6 km (25,000 ft) a.s.l. and drifted NE.

Based on observation and video data, lava from Kliuchevskoi flowed down the NW flank on 29 March. On 31 March, lava bombs from Strombolian activity were projected about 100-200 m above the crater. According to a news article, lava flows are interacting with snow and ice and producing vapor plumes.

Karangetang volcano is still active as news reports suggest. An ash plume was observed rising to an altitude of 1.9 km (6,000 ft) a.s.l. on 27 March. Pyroclastic flows may have occurred the next day.

Tungurahua volcano continues with strong explosions producing eruption columns rising to 10-11 km and pyroclastic flows and lahars (mud-flows) on its flanks:

On 28 March, an eruption from Reventador produced an ash plume that rose to an altitude of 5.6 km (18,400 ft) a.s.l. and drifted W. A small lava flow traveled 200 m down the S flank. Incandescent material and ash emissions were observed during 29-31 March. On 1 April, ash plumes rose to an altitude of 7.6 km (24,900 ft)  a.s.l. and incandescent rocks were ejected about 50 m above the crater. Incandescent material was again seen at the summit on 2 April. The
Washington VAAC reported that a strong hotspot was present on satellite imagery during 1-3 April. Based on pilot reports, IG reported that a steam-and-gas plume with little ash content rose to an altitude of 6.1 km (20,000 ft) a.s.l. and drifted W on 3 April.

On 3 April, pilots observed lava and ash emissions from Ambrym volcano. Ash plumes rose to altitudes below 2.4 km (8,000 ft) a.s.l.

Thomas, our correspondant in Arusha climbed Lengai last week and reports indirect signs of activity near the western rim of the crater, at the place where lava overflowed in the March 2006 eruption.
this is his report:

The lava flow from Stromboli volcano stopped today.
Whether this is the end of the effusive eruption that had started 5 weeks ago and heralds the beginning of a new cycle of summit activity is still unclear.

As correctly predicted by the monitoring staff, new eruptive activity restarted at 10h00 local time on 1 April after a two-day pause. New lava fountains and flows are emerging from a fissure in the SE part of the Enclos. The lowest part of the eruptive fissure is only at 500 m elevation and lava flows have been advancing rapidly; at 14h00 local time, they were only 300 m away from the National Road RN2.

For the third time in this year, Piton de la Fournaise volcano erupted again at 11 pm on 30 of March. Just as the last one on 18 February, the eruption only lasted for 9 hours.
The eruption had been preceded by increasing seismicity at the volcano since late March and about two hours of strong tremor immediately before a fissure vent opened in the southern part of the Enclos caldera.
Unlike after the brief eruption in February, this time, seismicity continues and is concentrated along a line ESE from the summit. A reactivation of the eruption in the near future is considered likely.