Northern Mariana Islands Recent Status Report, Updates, and Information Releases

U.S. Geological Survey
Saturday, December 16, 2017, 10:52 AM ChST (Saturday, December 16, 2017, 00:52 UTC)

Report prepared by the U.S. Geological Survey.

16°21' N 145°40'12" E, Summit Elevation 2592 ft (790 m)
Current Volcano Alert Level: UNASSIGNED
Current Aviation Color Code: UNASSIGNED

As described earlier today in the Volcanic Activity Notice, we have moved Anatahan from GREEN to unassigned due to a lack of local monitoring at this volcano, with no foreseeable fix for the data flow in the near future. This shift means that at this time, no volcano in the CNMI has local, on-island monitoring equipment of the sort that would allow forecasts of eruptive activity.

Current capabilities are limited to detection of volcanic eruptive activity once it has begun. This is done through a combination of several monitoring techniques. First, an array of infrasound (pressure) sensors on Saipan allows detection of atmospheric disturbances caused by eruptions in near real time. Seismic sensors on Saipan would also allow the detection of distant signals such as would be generated by earthquakes greater than magnitude 2.0, strong volcanic eruptions, and possibly weaker submarine volcanic activity within 100 km of Saipan. Similarly, volcanic ash clouds sometimes produce lightning and, if such lightning is detected by the World Wide Lightning Location Network (WWLLN), the USGS would receive notification within minutes. Finally, satellite-based alerts from NOAA-NESDIS are sent to the USGS in near-real-time and are capable of detecting significant explosive volcanic activity.

Once volcanic activity is detected, we use a variety of satellite imagery to characterize the height and extent of the resulting ash cloud, if present. Our current capabilities will likely allow us to detect and characterize eruptions shortly after they occur, and then provide timely information about activity. We also use hydrophone data from Wake Island to confirm activity, but because of the speed of waves in ocean water, there is a lag time of about 25 minutes before signals generated in the CNMI would reach Wake Island.

For definitions of Aviation Color Codes and Volcano Alert Levels, see:


CNMI Homeland Security and Emergency Management

USGS Northern Mariana Duty Scientist (808) 967-8815

Satellite information, Washington VAAC