Hazard Notification System (HANS) for Volcanoes


U.S. Geological Survey
Thursday, September 1, 2022, 5:13 PM HST (Friday, September 2, 2022, 03:13 UTC)

14°13'48" S 169°27'14" W, Summit Elevation 3054 ft (931 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

The earthquake swarm related to Taʻū Island continues with no significant change in the past 24 hours. Preliminary data analysis suggests a wide area of possible earthquake locations extending from deep beneath Ta’u Island to shallower depths about 10 km (6 mi) to the north. The source of the earthquakes has not moved within the earth since monitoring began 3 weeks ago – the source position has remained constant. Seismologists continue to examine data and refine locations.  

In the past 24 hours, the USGS seismic network detected 27 earthquakes that were large enough to be felt by people on the Manuʻa Islands. The largest event has a preliminary magnitude of 3.2 and occurred at 3:49 AM SST this morning. Many small earthquakes undetectable by humans also continue.

No volcanic activity was observed in available satellite data from the previous 24 hours.

Samoan and English language alert level and color code definitions: (PDF download, 57.68 kb) https://www.usgs.gov/media/files/volcano-aviation-codes-and-alert-levels-english-and-samoan

Possible Hazards

It is unclear if this earthquake unrest will escalate to a volcanic eruption and exactly where an eruption might occur. An eruption could pose significant hazards to residents of American Samoa; these hazards include volcanic gases, volcanic ash, low-level localized explosions of lava, lava flows, earthquake shaking, and tsunami. Information about these hazards, which are like those in Hawaii, can be found at this HVO website: https://www.usgs.gov/observatories/hvo/hazards. 

The primary hazard of concern at this time is earthquake shaking, although no physically damaging earthquakes have occurred as part of this swarm. For information on how to prepare for an earthquake, see: https://www.usgs.gov/faqs/what-can-i-do-be-prepared-earthquake

If you feel shaking and are not near the coast, immediately drop, cover, and hold on until the shaking stops. If you are at the coast, heed the natural tsunami warning signs. If you feel a strong or long-duration earthquake, see a sudden rise or fall of the ocean, hear a loud roar from the ocean, or see a large aerial plume from an eruption, a tsunami may follow, and you should immediately move to higher ground.  Pacific Tsunami Warning Center: https://tsunami.gov/

Volcano Monitoring

Volcanoes in the Manuʻa Islands are monitored with a limited real-time seismic network consisting of three sophisticated seismometers —two on Taʻū Island and one on Ofu Island—and six microseismometers on Tutuila, Taʻū, and Ofu-Olosega Islands. Satellite remote sensing is another tool being used, which may detect heat, volcanic gas, and volcanic ash associated with early phases of volcanic activity.

Report what you feel and see.

Residents can assist these monitoring efforts by noting and reporting accurate times that they feel earthquake shaking or notice other changes that might be related to volcanic activity to either the Pago Pago National Weather Service Office (https://www.weather.gov/ppg/wsopagooffice) or the American Samoa EOC in Pago Pago (684-699-3800).  

American Samoa Volcanoes

Volcanoes in the U.S. Territory of American Samoa are within the area of responsibility of the U.S. Geological Survey’s Hawaiian Volcano Observatory, based in Hilo on the Island of Hawai‘i.

NOAA Weather and Tsunami resources

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawaiʻi and American Samoa.


HVO, askHVO@usgs.gov—best contact for regular reporting and questions. 
Ken Hon, HVO Scientist in Charge, USGS khon@usgs.gov
Natalia Deligne, American Samoa Lead Responding Scientist, USGS ndeligne@usgs.gov 

Subscribe to these messages: https://volcanoes.usgs.gov/vns2/
Summary of volcanic hazards from eruptions: https://www.usgs.gov/observatories/hvo/hazards
Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/observatories/hvo
Volcanoes of American Samoa: https://www.usgs.gov/observatories/hvo/volcanoes-american-samoa
Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/programs/VHP/volcanic-alert-levels-characterize-conditions-us-volcanoes