Local news reported, "hot clouds" and incandescent material from Merapi travelling a distance of 1 km SE down the Gendol River on 23 May. People in the nearby village of Muntilan, about 16 km W, told about "hot clouds" & ashfall.

Based on a Significant Meteorological Information (SIGMET) advisory and satellite image observations, the Buenos Aires VAAC reported that ash plumes from Llaima rose to altitudes of 3-4.3 km (10,000-14,000 ft) a.s.l. on 26 May. The plumes were visible on satellite imagery drifting E. On 28 May, a pilot reported that an ash plume rose to 5.5-6.7 km (18,000-22,000 ft) a.s.l. and drifted E.

8-25 May: Seismic activity at Kliuchevskoi continued above background levels and a thermal anomaly in the crater was detected on satellite imagery.

Scientists from PHIVOLCS conducted an aerial investigation of Bulusan and discovered lahar deposits and three steaming fissures. Scientists also observed steam plumes that rose to altitudes of 1.6-1.7 km.

INGEMMET reported that during 16-17 May, ash and gas plumes from Ubinas rose to altitudes of 5.8-7.7 km (19,000-25,300 ft) a.s.l. and drifted SW, SE, and E.Based on pilot reports and satellite imagery, the Buenos Aires VAAC reported that continuous emissions produced ash plumes that rose to altitudes of 5.6-9.1km (18,000-30,000 ft) a.s.l. during 17 and 19-22 May. Plumes drifted ESE, SE,and E.

During 15-22 May, IG reported that ash plumes intermittently visible from Tungurahua rose to altitudes of 5.1-7 km (16,700-23,000 ft) a.s.l. and drifted mainly W, NW, and E. Ashfall was reported from areas SW and W during 16-17 May, SW on 19 May, and W and NW during 20-21 May. Lahars and muddy waters traveled down W, NW, and N ravines during 15 and 17-19 May and caused the road to Bañosto close on 18 May. Lahars that traveled in the Bilbao sector and down NW ravines on 20 May blocked the Baños-Penipe highway and obstructed the route between Ambato and Baños for about 6 hours. Muddy waters traveled down ravinesto the N.

Data from deformation-monitoring instruments indicated that during 16-22 May 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.

Based on visual observations, MVO reported that during 11-21 May lava-domegrowth at Soufrière Hills likely ceased and the overall structure of the dome changed very little. Low-level rockfall and pyroclastic flow activity continued. Seismic activity was very low. The Alert Level remained at 4 (on a scale of 0-5).

KVERT reported that seismic activity at Shiveluch continued above backgroundlevels during 11-18 May. Based on seismic interpretation, ash plumes possibly rose to an altitude of 6 km (19,700 ft) a.s.l. throughout the reporting period.A large thermal anomaly was visible on satellite imagery. The Level of Concern Color Code remained at Orange.

Based on information from JMA and a pilot report, the Tokyo VAAC reported that ash plumes from Sakura-jima rose to altitudes of 1.2-2.7 km (4,000-9,000 ft) a.s.l. during 16 and 20-22 May. Plumes drifted NW on 16 May and rose straight up during 20-22 May.

On 16 May, IG reported that a steam plume from Reventador rose to an altitude of 3.6 km (11,900 ft) a.s.l. and drifted to the NW. The plume was visible on satellite imagery. On 18 May, strong rains resulted in a lahar that lasted approximately 40 minutes. A lahar was also noted on 22 May. Visual observations were hindered during most of the reporting period due to inclement weather.

During 16-22 May, lava from Kilauea continued to flow SE across a lava delta into the ocean at the Kamokuna entry. On 16 May, lava from the E arm of the Campout flow advancing along the coastal plain from the base of the Royal Gardens sub-division, reached the ocean at the newly-formed Poupou entry. On 18May, field crews reported that the Poupou entry, about 1.6 km E of the Kamokuna entry, was 20 m wide and building a delta. Incandescence was visible from several vents in the Pu'u 'O'o crater and from breakouts on, above, and at the base of the Pulama pali fault scarp. Earthquake activity that initially increased on 12 May was scattered beneath the upper rift zone and S-flank areas.

Seismic activity at Karymsky was slightly above background levels during 11-18May. On 13 May, a possible ash plume rose to an altitude of 1.7 km (5,600 ft)a.s.l. The Level of Concern Color Code remained at Orange.

Pumice from the Home Reef eruption that began early-to-mid August 2006 reached the eastern Australian coast in March 2007. A substantial stranding of the pumice in mid-April extended for more than 1,300 km along the Queensland and northern New South Wales coast. Pumice clasts ranged in size from 1-4 cm indiameter, with the largest clasts up to 17 cm in diameter. A visit to the area in February 2007 revealed a pumice mound barely visible over the waves.

RVO reported that white vapor emissions from Bagana's summit crater continued during 10 March-20 May. Emissions were occasionally forceful, and were accompanied by ash clouds during 17 March, 1 April, and 3-5 April. Weak roaring noises were heard on 4 April. Summit incandescence was visible on 20 and 24March and 17 May. Based on satellite imagery and information from RVO, the Darwin VAAC reported that a diffuse plume rose to an altitude of 3 km (10,000ft) a.s.l. and drifted SW on 20 May. RVO reported that forceful, white emissionson 21 May produced plumes to an altitude of 2.3 km (8,200 ft) a.s.l. and drifted W.

According to a news article, "sea surges" destroyed four homes and aboat following an eruption of Ritter Island on 19 May. About 1,500-2,000 peopleon Siassi Island moved to higher ground. Villagers reported seeing plumes from the island, hearing rumbling noises, and feeling earthquakes. The article also mentioned that RVO and the Geophysical Observatory in Port Moresby did not record any seismic activity from the eruption.

KVERT reported that during 11-22 May, seismic activity at Kliuchevskoi continued above background levels and a thermal anomaly in the crater was detected on satellite imagery. According to video data and visual observations, Vulcanian activity at the terminal crater and phreatic bursts at the NW flank of the volcano were observed on 11 and 16 May. Also on 11 and 16 May, ash plumes rose to 9.7 km (31,800 ft) a.s.l. and drifted E and NE, respectively. Clouds inhibited observation on other days. Ashfall was reported from the town of Klyuchi, about 30 km to the NE, during 11-12 and 16-17 May. KVERT raised the Level of Concern Color Code  from Orange to Red on 17 May.

PHIVOLCS reported on 20 May that seismicity from Bulusan remained high following the explosion on 12 May. Ground deformation measurements conducted on 17 May on the NE flank revealed 4 mm of inflation compared to the previous measurement on7 April. The Alert Level was raised from 1 to 2 (out of 5) due to the increased seismicity and inflation.

KVERT reported on 17 May that the Level of Concern Color Code for Bezymiannywas lowered to Yellow. Satellite imagery showed that the thermal anomaly decreased in size during 15-17 May. Hunters reported that a large mudflow, 200 min width, moved along the Sukhaya Khapitsa river on 17 May.

An explosion from Bulusan on 12 May produced an ash plume that rose to an altitude of 5.6 km (18,400 ft) a.s.l. and drifted WSW and WNW. The activity was accompanied by rumbling sounds and was recorded by the seismic network as an explosion-type earthquake that lasted about 35 minutes.

The explosive-effusive eruption of Klyuchevsy volcano continues and the alert level has been raised to red. Ash explosions more than 10 km (32,800 ft.) ASL could occur at any time. The activity of the volcano could affect international and local aircraft.
The amplitude of volcanic tremor has increased during last few days. According to visual data from Kozyrevsk and Klyuchy, an ash plume from the central crater about 9700 m (31900 ft) ASL was observed at 03:50 UTC on May 16 extending to the North. According to satellite data, ash plumes extended for 200-600 km (125-370 mi) to the north-east, north-west, and east from the volcano this week. A large thermal anomaly was noted all days.

Based on pilot reports and satellite imagery, the Buenos Aires VAAC reported that ash plumes from Ubinas rose to altitudes of 5.5-9.1 km (18,000-30,000 ft) a.s.l. during 2-5 May. Plumes drifted NE, S, SE, and SW.

IG reported that lahars and muddy waters that traveled into the Pampas sector and in W and NW ravines blocked the Baños - Penipe highway during parts of 3, 4, and 6 May.
During 2-3 and 5-7 May, ash plumes from Tungurahua rose to altitudes of 5.2-7 km (17,100-23,000 ft) a.s.l. and drifted NW and W.
Ashfall was reported in areas about 8 km to the SW and W during 3, 6, and 7 May.
The Washington VAAC reported that a diffuse ash plume was visible on satellite imagery drifting W on 8 May. Clouds occasionally inhibited visual observations during the reporting period.

Based on information from JMA, the Tokyo VAAC reported explosions from Suwanose-jima on 8 May. Ash was not visible on satellite imagery.

Data from deformation-monitoring instruments indicated that during 2-8 May 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 27 April-8 May, visual observations suggested that lava-dome growth at Soufrière Hills continued at a reduced rate or ceased.
Fresh deposits were evident at the head of Tyres Ghaut to the NW, the upper parts of Farrell's Plain and Tuitt's Ghaut to the N, and the upper parts of the Tar River Valley to the E. Pyroclastic activity was ongoing on the E and NE sides of the dome during 27 April-4 May and pyroclastic flows were observed in the Tar River Valley and on Farrell's plain, into Tuitt's Ghaut.

KVERT reported that seismic activity at Shiveluch continued above background levels during 27 April-4 May.
Based on seismic interpretation, observation, and video data, ash-and-steam plumes possibly rose to altitudes of 4-10 km (13,100-32,800 ft) a.s.l. throughout the reporting period.
Plumes were seen on satellite imagery drifting S and SW during 28-29 April and a thermal anomaly was present during 27 April-4 May. Based on visual and video data, hot avalanches originating from the lava dome were observed on 30 April.
Based on information from the KEMSD, the Tokyo VAAC reported that an ash plume rose to an altitude of 4.9 km (16,000 ft) a.s.l. on 7 May. The Level of Concern Color Code remained at Orange . According to a news article, a mud avalanche damaged a 30-m stretch of road which links a district center in the east of the peninsula with the rest of the territory in the region.

Based on satellite imagery and information from CVGHM, the Darwin VAAC reported diffuse ash plumes from Semeru at an altitude of 4.6 (15,000 ft) a.s.l. during 3-5 May. The plumes drifted SW.

Based on pilot observations, the Washington VAAC reported that an ash plume from Sangay rose to altitudes of 5.2-7.6 km (17,000-25,000 ft) a.s.l. on 4 May. On 5 May, a possible narrow ash plume was visible on satellite imagery drifting W.

RVO reported that during 29-30 April, ash emissions from Rabaul caldera's Tavurvur cone generated plumes that rose to an altitude of 1.2 km (3,900 ft) a.s.l. and drifted W. During 1-2 May, ash plumes drifted NNW; ashfall was reported from Rabaul town and surrounding areas. Occasional roaring noises were heard and incandescence was observed at night.

RVO reported that Manam's Main Crater and South Crater occasionally released white vapor plumes during 1-5 May. Weak incandescence was visible from Main Crater on 2 and 4 May. Seismicity was at low levels. Based on information from RVO and satellite imagery, the Darwin VAAC reported that a diffuse plume drifted W on 6 May.

Based on observations and video data, KVERT reported that Strombolian activity occurred at Kliuchevskoi during 27 April-4 May.
Seismic activity continued above background levels and a thermal anomaly in the crater was detected on satellite imagery.
Mudflows and lava flows continued to advance on the NW flank. Phreatic activity and ash plumes from lava-flow fronts were noted.
Gas-and-steam plumes containing ash rose to altitudes of 6.2 km (20,400 ft) a.s.l. during the reporting period and were visible on satellite imagery drifting S and SE. Based on information from KVERT, the Tokyo VAAC reported that ash plumes rose to an altitude of 5.2 (17,000 ft) a.s.l. and drifted NE on 3 May.
According to a news article, an ash plume rose to altitudes of 5.3-5.5 km (17,400-18,000 ft) a.s.l. and drifted NE on 7 May. Ashfall was reported from the town of Klyuchi, about 30 km to the NE. The Level of Concern Color Code remained at Orange

During 2-8 May, lava from Kilauea continued to flow SE across a lava delta into the ocean at the Kamokuna entry. Incandescence was visible from several vents in the Pu'u 'O'o crater and from breakouts on, above, and at the base of the Pulama pali fault scarp.
Earthquake activity was scattered at the summit, upper E rift zone, and S-flank areas. Tremor remained at moderate levels.

During 3-4 May, large channelized a'a' flows descended down the pali on the Campout flow.
On 4 May, a sheet flow ponded lava at the base of the Royal Gardens sub-division.
On 8 May, HVO scientists reported that for the past several months, Kilauea caldera widened at a rate of 1.5 cm/month and Pu'u 'O'o cone was slowly collapsing, as indicated by new cracks on the S flank. Subsidence of the cone's N flank at a rate of 1 cm/month was also measured.

Seismic activity at Karymsky was above background levels during 27 April-4 May. A thermal anomaly was visible on satellite imagery; ash plumes were absent. The Level of Concern Color Code remained at Orange

Based on satellite imagery and CVGHM, the Darwin VAAC reported that a diffuse ash plume from Batu Tara drifted W on 5 May.

The Wellington VAAC reported that a pilot observed an ash plume from Ambrym on 3 May. The plume rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted SE. Ash was visible on satellite imagery.

On 6 May, scientists from OVSICORI declared a Low Alert Level for Turrialba based on rapid changes during the previous three months, and intensified their fieldwork and data collection efforts. During aerial observation in February 2007, trees looked yellowish due to sustained gas emissions from the W crater. Vegetation growth was noted in previously burned areas on the W and SW flanks near the summit. On 21 April, a hot area (40º C) was noted 1.5 km SW of the summit, at the base of the volcanic edifice, that coincides with the WSW-ENE-trending Ariete fault. On 2 May, two larger hot and fuming spots were documented along the same fault, about 200 m SW of the first area. The vapor plumes were spotted from several kilometers away, above the forest canopy. Heat destroyed vegetation in an approximately 300 square m area along the S fault's plane.

OVPDLF reported that the eruption of Piton de la Fournaise ceased on 1 May. During 2-7 May, seismicity continued at and below the summit, and also indicated a large number of landslides from Dolomieu crater walls.

Based on a pilot report, the Wellington VAAC reported that an ash plume from Lopevi rose to an altitude of 2.1 km (7,000 ft) a.s.l. on 3 May.

A new short-lived but intense summit eruption (paroxysm) took place at Etna volcano on the afternoon of 29 April. Following a large increase in seismic activity from 11h00 loacl time, the eruption started at around 16:00 with lava fountaining and ash emission from the SE crater. Lava flows that travelled into the Valle del Bove were emitte from vents at the base of the SE crater. The eruption ended abruptly shortly after midnight early on 1 May.