Archived Updates

Tuesday, September 9, 10:00 a.m. local Anatahan time

For the past 24 hours, Anatahan volcanic seismicity has been low, at a level similar to that since June. There were no apparent eruption signals or precursory events.

Wednesday, September 10, 10:00 a.m. local Anatahan time

For the past 24 hours, Anatahan volcanic seismicity has been low, at a level similar to that since June. There were no apparent eruption signals or precursory events.

A small regional event coming from south of Saipan at about 90 km slant distance was recorded at 2035 UTC.

Thursday, September 11, 10:00 a.m. local Anatahan time

Anatahan volcanic seismicity has remained low, at a level similar to that since June. There were no apparent eruption signals or precursory events.

No significant regional activity was recorded by the seismic network.

Friday, September 12, 10:00 a.m. local Anatahan time

Anatahan volcanic seismicity has remained low, at a level similar to that since June. There were no apparent eruption signals or precursory events.

Two small regional events were recorded by the seismic network. The first, occurring at 0040 UTC, was roughly equidistant from Anatahan and Sarigan, at a slant distance of about 60 km. The second, occurring at 0247 UTC, appeared to be roughly due north of Saipan, at a slant distance of about 65 km from the Emergency Management Office, and about 90 km from Anatahan.

Visual observations of the volcano were made four times during the past two weeks.

On August 30, USGS and EMO personnel took an overflight of Anatahan.  There were no ash emissions.  The feeble plume was dominated by steam and lesser amounts of volcanic gases, mainly SO₂.  Emissions were sporadic, occasionally rising high enough to clear the crater rim.  From afar the plume looks like cumulus clouds.

The floor of the east crater is covered by dirty, sediment-laden, steaming water.  Sulfurous gases are being emitted from cracks in the crater walls and floor. 

USGS and EMO personnel flew over Anatahan on September 8, 9, and 11 and  reestablished the original, pre-eruption Anatahan seismic station.  The signal is now being received at EMO and will soon to come on line.

Conditions in the crater resembled those on August 30. The floor of the crater continues to be covered by sediment-laden water. An active geothermal system in the east crater consists of mud pots, mini-geysers, and steam jets from the crater walls.

Saturday, September 13, 10:00 a.m. local Anatahan time

Anatahan volcanic seismicity has remained low, at a level similar to that since June. There were no apparent eruption signals or precursory events.

Thunderstorm activity in the region has resulted in a higher than average number of background microseisms.

A magnitude 6 earthquake in the New Britain region of Papua New Guinea triggered the RSAM alarm shortly after 0700 UTC, and a distant regional at a slant distance of about 300 km north of Saipan was recorded by the network at 0951 UTC.

Sunday, September 14, 10:00 a.m. local Anatahan time

Anatahan volcanic seismicity has remained low, at a level similar to that since June. There were no apparent eruption signals or precursory events.

No significant regional seismicity was recorded by the network.