AVO reported that during 14-15 and 18-19 May elevated surface temperatures over Cleveland were observed in satellite images. Clouds obscured views during 16 and 20-21 May. Satellite image analysis revealed that a small lava flow had breached the SE rim of the summit crater and traveled as far as1.5 km down the flank. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: Alaska Volcano Observatory (AVO)

AVO reported that during 8-9 May no further explosions had been detected at Cleveland based on regional infrasonic data. Cloud cover prevented satellite observations of the crater. Clear satellite views revealed vigorous steam plumes during 10-11 May and thermal anomalies during 10-14 May. On 14 May AVO noted that analysis of recent satellite imagery revealed a 100-m-wide lava flow, breaching the SE rim of the summit crater, and extending about 1.5 km down the SE flank. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.

Source: Alaska Volcano Observatory (AVO)

OVDAS-SERNAGEOMIN reported that an explosion from Copahue at 1015 on 7 May recorded by a webcam produced a gas, steam, and ash plume that rose 350 m and drifted SE. Incandescence from the crater was visible at night. The Alert Level was raised to Yellow.

Source: Servicio Nacional de Geología y Minería (SERNAGEOMIN)

CVGHM reported that on 28 March gas emissions continued to be elevated at Timbang, a cone that is part of the Dieng Volcanic Complex. Plumes containing carbon dioxide drifted 2 km towards the S valley of Kali Sat, prompting a road closure until the early evening when the gas concentration decreased. On 30 March carbon dioxide gas emissions were not detected; however, "smoke" rose at most 100 m above the crater. Hydrogen sulfide odors were very potent in areas 1 km W and weak in areas 1.5 km S. On 19 April sulfur dioxide odors were reported. On 24 March Sileri Crater lake water changed from dark gray to brown. On 7 April white plumes rose 50 m and the water color returned to normal. Diffuse white plumes rose 15 m on 20 April. Other craters had not exhibited any changes by 28 April. Based on gas concentrations, seismicity, and visual observations, CVGHM raised the Alert Level to 3 (on a scale of 1-4) on 8 May and warned the public not to approach Timbang Crater within a 500-m radius.

Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

CVGHM reported that in early March a slight increase of deep and shallow volcanic-tectonic earthquakes at Guntur was recorded; volcanic tremor became continuous on 2 April, prompting CVGHM to raise the Alert Level to 2 (on a scale of 1-4). Temperature measurements of hot springs in five different areas fluctuated until mid-April and then were relatively stable through early May. Seismicity also decreased in early May. On 7 May the Alert Level was lowered to 1.

Source: Center of Volcanology and Geological Hazard Mitigation (CVGHM)

At 0800 on 8 May, PHIVOLCS reported that two rockfalls at Mayon had been detected within the previous 24 hours. Seismicity remained within background levels and indicated no increase in overall volcanic activity. The Alert Level remained at 0 and the public was reminded not to enter the 6-km-radius Permanent Danger Zone (PDZ).

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

AVO reported that on 13 May seismicity at Pavlof increased at 0800 commensurate with the presence of an intense thermal anomaly at the summit observed in satellite imagery. Several spikes in seismicity occurred between 0900 and 1000. AVO noted that similar patterns of seismicity and elevated surface temperatures have previously signaled the onset of eruptive activity at Pavlof. Although not yet visually confirmed at the time of the report, a low-level eruption of lava had likely begun from a summit vent. No ash clouds were detected. The Volcanic Alert Level was increased Watch and the Aviation Color Code was increased Orange. On 14 May pilot reports and satellite images confirmed activity; a spatter-fed lava flow advanced about 0.5 km down the N flank. Minor steam-and-ash emissions from the summit were visible from Cold Bay (60 km SW).

Source: Alaska Volcano Observatory (AVO)

CENAPRED reported that an episode of high-amplitude spasmodic tremor detected at Popocatépetl began between 1928 on 7 May and 0159 on 8 May. The seismic increase was accompanied by an ash plume that rose 3 km above the crater and drifted SE, producing ashfall in San Pedro Benito Juarez (10-12 km SE), San Juan Tianguismanalco (22 km SE), Atlixco (23 km SE), and in some areas of Puebla (~50 km to the E). Incandescent tephra ejected from the crater landed 500 m away on the NE flank. On 8 May an explosion produced an ash plume that drifted SE. Incandescence from the crater was observed at night. The next day gas-and-steam plumes drifted SE. On 10 May steam, gas, and ash plumes were detected; one of two explosions produced an ash plume that drifted E. A series of ash emissions and periods of harmonic tremor occurred between 1142 and 1443; cloud cover prevented clear views of the ash plumes. On 11 May steam, gas, and ash plumes were again detected. An explosion produced an ash plume that rose 1 km and drifted NE, and ejected incandescent tephra 500 m down the NE flank. Ash possibly fell in villages downwind. Gas-and-ash plumes rose 0.1-2 km and drifted ENE and NE. During 11-12 May periods of spasmodic and harmonic tremor were detected, and activity increased overall. On 12 May CENAPRED noted that there had been an increase in activity during the previous two weeks, and another intensification that day prompting the Alert Level to be raised to Yellow, Phase Three. Access to the crater within a 12-km radius was prohibited. Stream-and-gas plumes with small amounts of ash rose from the carter. Sporadic ejections of incandescent tephra fell back into the crater and onto the NNE flank, 300 m from the crater rim. On 13 May steam-and-gas plumes were observed rising from the crater during periods of good visibility. On 14 May an explosive event generated an ash plume that rose 3 km and ejected incandescent tephra that landed 600 m away on the NE flank. Cloud cover again obscured summit views. Seismicity remained elevated.

Source: Centro Nacional de Prevencion de Desastres (CENAPRED)

IG reported that although cloud cover often prevented observations of Tungurahua during 8-14 May, ash plumes were observed almost daily. Seismicity remained at a moderate level. Explosions occasionally vibrated structures nearby and at the Tungurahua Observatory (OVT) in Guadalupe (14 km N). Strombolian activity was observed on most nights ejecting blocks sometimes 500 m above the crater; blocks that fell onto the flanks rolled as far as 1 km. During 9-10 May lava fountains rose 700 m above the crater. During 8-11 May ash plumes rose 1-2.5 km and drifted SW, W, and NW, producing ashfall in El Manzano (8 km SW), Choglontus (SW), Quero (20 km NW), Mocha (25 km WNW), Pillate (8 km W), Tisaleo (29 km NW), and Penipe on 8 and 10 May, and in Santa Fe de Galán, Mocha, Sabañag (15 km WNW), Tisaleo, and Quero (20 km NW) on 11 May. Ashfall was reported in Quero on 12 May. The next day explosions generated ash plumes that rose 2-3 km and drifted NW and W, producing ashfall in El Manzano. Roaring and sounds resembling rolling blocks were reported. On 14 May ash fell in Choglontus, El Manzano, and Mocha.

Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)

During 8-14 May HVO reported that the circulating lava lake occasionally rose and fell in the deep pit within Kilauea's Halema'uma'u Crater. The plume from the vent continued to deposit variable amounts of ash, spatter, and Pele's hair onto nearby areas. At Pu'u 'O'o Crater, glow emanated from three spatter cones and a small lava pond on the E part of the crater floor. Lava from the E lava pond traveled down the N, NE, E, and S flanks, extending beyond the base of Pu'u 'O'o cone. During 10-11 May the SW spatter cone erupted lava, and during 11-12 May the SE spatter cone also produced flows. Peace Day activity, fed by lava tubes extending from Pu'u 'O'o, consisted of lava flows active on the pali and on the coastal plain. Lava also entered the ocean in at least two locations spanning the National Park boundary.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

KVERT reported that during 3-10 May moderate seismic activity continued at Kizimen. Video and satellite data showed that lava continued to extrude from the summit, producing incandescence, strong gas-and-steam activity, and hot avalanches on the W and E flanks. A thermal anomaly was detected daily in satellite images. The Aviation Color Code remained at Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 13 May ash plumes from Paluweh rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted over 90 km WNW and NW.

Source: Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 13 May ash plumes from Paluweh rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted over 90 km WNW and NW.

IG reported that during the morning of 8 May incandescence from Reventador's crater was observed in addition to steam-and-ash plumes that rose 1 km above the crater and drifted NW. Cloud cover prevented observations the rest of the day and most of the time during 9-14 May. At 1700 on 10 May a steam plume with low ash content rose 1 km above the crater, and on 11 May a vapor plume rose 500 m and drifted SW.

Source: Instituto Geofísico-Escuela Politécnica Nacional (IG)

On 10 May Instituto Geofísico de Perú (IGP) reported that results of an interferogram of Sabancaya provided by a collaborator at Cornell University showed that an area of deformation (subsidence of 7 cm centered at 6 km NE of the crater) was coincident with the main area of seismicity. Volcano-tectonic (VT) earthquakes continued to dominate the seismic signals, although long-period (LP) events continued to be detected. There was also an increase of hybrid events. On 10 May a M 4 VT event occurred 15 km W and fumarolic activity increased, with plumes rising 1.2 km high.

Source: Instituto Geofísico de Perú (IGP)

JMA reported that during 7-10 May eight explosions from Sakura-jima's Showa Crater ejected tephra that fell at most 1.8 km from the crater. Crater incandescence was occasionally detected at night. Based on information from JMA, the Tokyo VAAC reported that on most days during 8-14 May explosions produced plumes that rose to altitudes of 2.1-4.3 km (7,000-14,000 ft) a.s.l. and drifted in multiple directions. During 9 and 13-14 May pilots observed ash plumes rising to altitudes of 2.4-3 km (8,000-10,000 ft) a.s.l. and drifting N, NW, and W.

Sources: Japan Meteorological Agency (JMA), Tokyo Volcanic Ash Advisory Center (VAAC)

Based on visual observations and analyses of satellite data, KVERT reported that during 3-10 May a viscous lava flow effused on the NW and NE flanks of Shiveluch's lava dome, accompanied by hot avalanches, incandescence, and fumarolic activity. Satellite imagery showed a daily thermal anomaly on the lava dome. The Aviation Color Code remained at Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

KVERT reported that the S fissure along the W side of Tolbachinsky Dol, a lava plateau on the SW side of Tolbachik, continued to produce very fluid lava flows during 3-10 May that traveled to the W, S, and E sides of the plateau. Cinder cones continued to grow along the S fissure and gas-and-ash plumes were observed. A large thermal anomaly on the N part of Tolbachinsky Dol was visible daily in satellite imagery. The Aviation Color Code remained at Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

AVO reported that on 4 May the infrasound network detected three short-duration explosions from Cleveland at 0500, 0717, and 1144. A small, low-altitude ash cloud along with high surface temperatures at the summit were observed in satellite images starting at 0717. In a report posted at 1822 AVO noted that both webcam and satellite images suggested continuous low-level emissions of gas, steam, and minor amounts of ash over the past several hours with a faint plume drifting E below 4.6 km (15,000 ft) a.s.l. The Volcanic Alert Level was raised to Watch and the Aviation Color Code was raised to Orange.On 5 May the amplitude of the Cleveland infrasonic tremor, as measured by the ground-coupled airwaves on the Okmok seismic network, 120 km NE, decreased from its peak activity the evening before. Satellite images again detected continuous low-level emissions of gas, steam, and minor amounts of ash producing a faint plume that drifted E below 4.6 km (15,000 ft) a.s.l. Explosions were detected at 1123 on 5 May and 0800 on 6 May. A thermal anomaly continued to be detected. A news article stated that some airplanes were diverted away from Cleveland.

Sources: Alaska Volcano Observatory (AVO), Reuters

According to NASA Earth Observatory (EO) an image acquired on 7 April from the Advanced Land Imager (ALI) on NASA's EO-1 satellite showed that Mawson's Peak crater on Heard Island had filled and a lava flow had traveled down the SW flank. The lava flow was visible in an image acquired on 20 April and had slightly widened just below the summit.

Source: NASA Earth Observatory

PHIVOLCS reported that a small phreatic eruption from Mayon occurred at 0800 on 7 May and lasted for 2 minutes and 26 seconds. A gray-to-brown ash cloud rose 500 m above the crater and drifted WSW. Ash fell in areas WNW, affecting the barangays of Muladbucad (10 km WSW), Guinobatan (11 km SW), Nabonton (10 km W), Nasisi (11 km W), Basag (10 km W), Tambo, Ligao City (19 km WSW), Albay (19 km SW), and areas upslope of these barangays. One rockfall was detected. Seismicity and gas emissions remained within background levels and indicated no intensification of activity. The Alert Level remained at 0 and the public was reminded not to enter the 6-km-radius Permanent Danger Zone (PDZ).According to a news article, the eruption ejected large "room-sized rocks" towards about 30 climbers, killing five and injuring eight.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), ABC News