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.

Anatahan volcano, violently active in 2003-05, is showing increased fumarolic and seismic activity. Its Volcanic Alert Level was increased from Normal to Advisory.

Anatahan volcano is continuing to emit gas and steam, but no significant ash emissions have been observed during the past few months.

Based on a pilot report, the Washington VAAC reported that an ash plume from Anatahan reached an altitude of 3 km (10,000 ft) a.s.l. on 29 May and drifted W.Emissions from the E crater of vog (volcanic fog), steam, and a gas plume were visible on satellite imagery at about 1333 and increased prior to generation of the ash plume. A report issued from the Washington VAAC on 30 May at 05:35 indicated a faint, low-level gas-and-ash plume extending from the summit.

Ash plume from Anatahan volcano on 19 March 2006 (NASA).

Anatahan volcano shows new activity. The volcano emitted a moderately large plume of ash on March 19, 2006 as was detected by the Moderate Resolution Imaging Spectroradiometer (MODIS) flying onboard the Aqua satellite.

Satellite imagery has not shown visible ash emissions from Anatahan since September 03, 2005. AFWA and the Washington VAAC continue to watch the volcano.

No reports of activity from Anatahan volcano have been received since 3 September, which indicates that the eruption might be over.

ANATAHAN Mariana Islands, central Pacific Ocean 16.35°N, 145.67°E;

Eruptive activity continues at Anatahan volcano in the Mariana Islands. Ash plumes, mainly observed by satellite and pilots, rise to heights of ~7.9 km (26,000 ft) a.s.l. Seismic activity continues at moderate levels.

Anatahan volcano remains in constant activity, with frequent explosions that produce an ash plume drifting at about 20,000 ft elevation and extending up to 200km.

As the USGS reports, a strong explosion occurred at Anatahan on 3 July at 16h46 local time. It produced a SSE-drifting plume reaching a height of ~12.2 km  (~40,000 ft) a.s.l. Volcanic fog (vog) was reported to have drifted over the southern parts of the islands of Saipan and Tinian. During the rest of the last week, steam and ash emissions were at lower levels.

As the USGS reports, seismicity at Anatahan volcano remains high. On June, 20, another powerful explosion that lasted 2-3 mintues sent an ash plume to a height of 20,000 ft (ca. 6 km). A plume located at the 10,000 ft level is extending for about 375 nautical miles (ca. 630 km)  NNW and from there, a thin plume is travelling further N for another 816 nautical miles (ca. 1300 km). 

The eruption at Anatahan continues at high levels. Frequent small to medium-sized explosions are occurring daily, during times of increased activity as often as every ten to twenty seconds. A dense ash and steam cloud is riging to 10,000 feet (ca. 3 km) and moving west at 10-15 knots. It extends about 100 nautical miles west, then thin ash and volcanic haze (vog) extends another 700 nm west beyond that. The plume then turns north-northeast and reaches as far north as 25 degrees latitude.

Example of a chart publisherd by the Washington DC Volcanic Ash Advisory Center (Washington VAAC), showing the ash plume from Anatahan volcano at flight level 150.

As the USGS reports, a huge eruption, the second largest eruption since the reawakening of Anatahan on May 10, 2003, ocurred on June 12. The eruption consisted of two explosions that started at 16h22 local time, lasting 3 minutes and one at 16h31 that lasted two minutes.

Volcanic activity continues at Anatahan volcano at moderate levels. The volcano emits ash clouds that rise up to about 4-5 km above sea level, and are drifting westwards extending for more than 500 km, nearly reaching the Philippines. Aircraft are derouted to avoid the potentially dangerous ash cloud.

During the past 48 hours, volcanic tremor beneath Anatahan increased to eight times the pre-May 18th background level. Discrete earthquakes are largely absent from the seismic record and acoustic records show no apparent explosive events. Satellite imagery indicates ash propagation at 10,000 feet beginning to shift from the southeast to the northwest. Vog and steam is apparent from visual imagery in two regions, the first between 50 and 55 nautical miles northeast of Anatahan, and a wider swath extending from 45 to 130 nautical miles southeast of Anatahan.

This image was released by NASA Tuesday April 5, 2005; it shows a thick cloud of ash erupted from the Anatahan Volcano, Mariana Islands (Pacific Ocean). According to the Washington Volcanic Ash Advisory Center, a series of low-level eruptions starting on April 4 have created this plume.

A large explosive eruption occurred at Anatahan volcano, Mariana Islands (Pacific Ocean) at 0300 on April 6 (local time), 1700 April 5 UT. The eruption produced an ash plume that reached the highest altitude thus far during its current eruption - about 50,000 feet (ca. 16 km).