According to news reports, a small eruption at Asama around 1530 on 14 September produced an ash plume that rose 1-2.5 km above the volcano. A smaller eruption earlier that day around 0328 produced a plume to ~300 m above the volcano. A small amount of ash fell in Takasaki, Gunma Prefecture ~45 km from the volcano.

Sources: Kyodo News, Tokyo Volcanic Ash Advisory Center (VAAC), Reuters

A news article reported that an eruption at Egon on 13 September produced an ash plume that drifted ~70 km downwind according to an Indonesian volcanologist. No ash was visible on satellite imagery. There were no reports of injuries or deaths. About 2,200 villagers living on the volcano's slopes had been evacuated since July 2004. Many of the evacuees reported experiencing respiratory problems and skin irritation. The airport in the town of Maumere was closed due to up to 1 cm of ash deposited on facilities and equipment.

Sources: The Jakarta Post, Associated Press, Darwin Volcanic Ash Advisory Centre (VAAC)

INGV-CT reported that at about 1030 on 7 September an effusive eruption began at Etna's summit. An approximately 230-m-long fissure opened at the base of Southeast Crater without any significant accompanying seismicity. Lava flowed from the base of the fissure, spreading SE towards the Valle del Bove. After 2 days of slow expansion of the field of fractures, between 0600 and 0700 on 10 September a new effusive vent opened at 2,650-m elevation on the upper western flank of the Valle del Bove. A lava flow poured out from this vent towards the E, spreading on the upper wall of the Valle del Bove. No explosive activity accompanied the emission of lava, but some phreatic explosions were triggered by lava flowing on a thick layer of snow. By 0930 the longest branch of the lava flow was 300 m long and 50 m wide. On the afternoon of 13 September, another effusive vent opened within the Valle del Bove, at about 2,200-m elevation, about 500 m SE of the previous vent. A lava flow from this vent spread in the valley at low output rate, while the previous flow from the vent at 2,650 m continued to feed a 1-km long lava flow. No lava flows threatened villages; the closest lava flow was at least 10 km from the nearest village.

Source: Sezione di Catania - Osservatorio Etneo (INGV)

HVO reported that beginning in early July 2004 an increasing number of earthquakes had been recorded beneath Mauna Loa. From week to week, the numbers fluctuated but remained well above the norm. Through the first week of September, more than 350 earthquakes were centered beneath Mauna Loa's summit caldera and the adjacent part of the southwest rift zone. Most of these earthquakes were quite deep, from 35 to 50 km below the ground surface. They were "long-period" (LP) earthquakes, which means that their signals gradually rise out of the ambient seismic background. Such a concentrated number of deep LP earthquakes from this part of Mauna Loa is unprecedented, at least in the modern earthquake catalog dating back to the 1960s. Inflation continued at the summit and as of 12 September showed no change during the increased seismic activity.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

On 12 September, faint glow was visible at Mayon's summit that coincided with a slight increase in overall background tremor. According to PHIVOLCS, these observations indicated a possible renewed episode of volcanic unrest, probably due to small incremental intrusions of magma at shallow depths that caused the intensified glow at the summit. They reported that small explosions, similar to the events on 3 June and 22 July 2004, may be expected as pockets of gas beneath the crater are suddenly released. There were no significant changes in ground deformation or sulfur-dioxide flux. According to a news report, volcanic material was emitted from Mayon late on 12 September, setting fire to grass on the volcano's slopes. People were reminded to remain outside of the 6-km Permanent Danger Zone. Mayon was at Alert Level 2 (on a scale of 0-5).

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)

During 8-13 September, small explosions at Fuego produced low-level plumes and avalanches of volcanic blocks traveled down the volcano's flanks. On 12 September a small lahar occurred down the volcano's flank.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

During 3-10 September, seismicity was above background levels at Karymsky. The number of shallow events increased from 55 to 250 during 3-6 September. Based on interpretations of seismic data, several plumes from ash-and-gas explosions may have risen 4.5-5.5 km a.s.l. A pilot observed an ash plume at a height of ~ 4 km a.s.l. on 5 September. Karymsky remained at Concern Color Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

During 9-12 September, a small amount of surface lava was visible atop Kīlauea's Pūlama pali and all vents in the crater of Puʻu ʻŌʻō were incandescent. Seismicity at Kīlauea's summit was low and tremor at Puʻu ʻŌʻō was moderate. Small episodes of deflation and inflation occurred during the report period.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

During 8-14 September, several weak-to-moderate explosions at Santa Maria's Santiaguito lava-dome complex produced ash clouds to a maximum height of ~1 km above the volcano. Partial collapses of the lava dome caused several pyroclastic flows to travel down the volcano's SW flank.

Source: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH)

Seismicity was above background levels at Shiveluch during 3-10 September, with several weak earthquakes occurring 0-5 km beneath the active lava dome. On 6 September at 2054 an explosion produced small pyroclastic flows and an ash plume that rose to ~5.5 km a.s.l. Shiveluch remained at Concern Color Code Orange.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)

Volcanic and seismic activity at Soufrière Hills remained at low levels during 3-10 September. The seismic network recorded two rockfalls and one volcano-tectonic earthquake. Sulfur-dioxide flux ranged between 175 and 405 metric tons per day, averaging 270 metric tons daily. A small pond, first observed during the week of 27 August, was still visible in the explosion pit formed on 3 March 2004.

Source: Montserrat Volcano Observatory (MVO)

During 3-10 September, elevated levels of seismicity continued to be recorded at Spurr as has been the case for several weeks. About 90 earthquakes were recorded during the report period within 30 km of the summit, with about 13 occurring per day. Observations and photography during the week revealed that the ice pit located near the summit had enlarged substantially (currently about 150 m x 170 m), presumably as the roof of the meltwater basin continued to subside and collapse. Spurr remained at Concern Color Code Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)

During 9-13 September volcanic and seismic activity were at low levels at Tungurahua, with the occurrence of weak steam-and-ash emissions and sporadic long-period earthquakes.

Sources: Instituto Geofísico-Escuela Politécnica Nacional (IG-EPN), Washington Volcanic Ash Advisory Center (VAAC)

Both low-level tremor and intermittent bursts of tremor continued at Veniaminof during 3-10 September. AVO scientists believed these tremor episodes likely represented low-level ash-and-steam emissions similar to those observed during the previous 4 months. Minor emissions of ash and steam were occasionally seen on the web camera during clear weather. Veniaminof remained at Concern Color Code Yellow.

Source: US Geological Survey Alaska Volcano Observatory (AVO)