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USGS seismic equipment now monitoring Manu’a earthquakes

USGS VOLCANO LOGO
Scientists warn this is not an immediate answer — it will take time
Joyetter@samoanews.com

Pago Pago, AMERICAN SAMOA — Scientists with the US Geological Services (USGS) in Manu’a have yet to determine the source of earthquakes occurring on a daily basis as there is a need for more assessments and that requires time. According to the latest USGS report, it will probably be 1-2 weeks before the advanced seismic network installation is tested and fully operational.

Dr Jefferson Chang said the volcano near Ta’u village they looking at will require time to determine what is happening — it’s like watching for water boil.

 “You just look at it, it’s not going to boil and at the same consider if this is normal or is this something new. Also it’s not just one analysis — the team comprises of a lot of different people with different backgrounds, with different techniques to look at it and with their interpretation hopefully we can tell [that to] the people of Manu’a.”

Chang is assisted by Elinor Lutu-McMoore head of the local Meteorology Office, Dr Drew Down and Dr Natalya Irma Delinge and this week they are installing seismometers to determine what is causing the earthquakes.

Dr Delinge said during a live feed from Manu’a on the US National Weather Service Pago Pago American Samoa’s Facebook page that the earthquakes are continuing.

 “And while that is an unpleasant experience for all of us here (in Manu’a) the more earthquakes that are happening the more we can diagnose the situation.

 “And so the current read is that if suddenly [the quakes] were to die away for example … then we would have the information to work with.

“And so the fact that these are continuing constantly are just providing us with additional examples of what is happening and that is really helpful for the team here back in the mainland.”

Dr Chang said they are putting in highly sensitive instruments that sense vibrations that cab pick up vibrations close by, like a wave or like cars driving — or even earthquakes distant near by such as Tonga or Asia.

 “We’re going to use this instrument to better determine what is causing the earthquakes in Fitiuta and around Manu’a and hopefully get data to pinpoint where these earthquakes are happening,” he said.

Adding that the instruments being installed will pick up more of the deep base sounds the volcano is producing.

According to the USGS latest data on August 22, 2022 there has been no significant change to the earthquake activity beneath or around Ta'u and Ofu-Olosega Islands since yesterday’s update.

USGS staff has identified sites on Taʻu Island for advanced seismometers and that began installation yesterday. 

 “It will probably be 1-2 weeks before the advanced seismic network is installed, tested, and operational.

 “Over the past several days approximately 20 earthquakes per hour have been recorded. Though the exact count isn't available, the number of recorded earthquakes in the past 24 hours appears slightly higher.

 “The estimated size of the largest earthquakes is between magnitude 2 and 3 and several felt earthquakes are reported each day. Preliminary estimates place the earthquake source closer to Ta’u Island than Ofo-Olosega. Reports of booming sounds on August 20 and the morning of 21 are being investigated. 

 “USGS scientists are monitoring the earthquakes with microseismometers (small and basic earthquake detectors) placed on Tutuila, Taʻu, and Ofu-Olosega Islands. Larger, more sophisticated, and accurate seismometers are being installed this week.

 “Data from the new equipment will help to accurately locate the earthquakes and develop better assessments of possible future hazards.”

 

Samoa News newsroom assistant Julie Pau’u contributed to this report.