{"id":155338,"date":"2022-02-10T09:14:22","date_gmt":"2022-02-10T19:14:22","guid":{"rendered":"https:\/\/www.hawaii.edu\/news\/?p=155338"},"modified":"2022-06-17T12:46:23","modified_gmt":"2022-06-17T22:46:23","slug":"hawaii-phones-tonga-blast","status":"publish","type":"post","link":"https:\/\/www.hawaii.edu\/news\/2022\/02\/10\/hawaii-phones-tonga-blast\/","title":{"rendered":"Hawai\u02bbi phones capture data in Tonga volcano blast"},"content":{"rendered":"Reading time: <\/span> 2<\/span> minutes<\/span><\/span>
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Tonga eruption visible from satellite. (Photo credit: NOAA<\/abbr>)<\/figcaption><\/figure>\n

The explosion of the underwater volcano Hunga Tonga-Hunga-Haʻapai<\/span> on January 15, released a blast “sound” wave that reverberated through Earth\u2019s atmosphere and was recorded around the world by monitoring stations—and smartphones. The devastating eruption produced the most powerful air blast since the 1883 eruption of Krakatoa in Indonesia.<\/p>\n

Monitoring systems at the University of Hawaiʻi<\/span> at Mānoa<\/a> that continuously listen for infrasound—deep, inaudible atmospheric sound produced by extreme natural events, such as volcanoes, asteroid impacts and intense explosions—recorded the Tonga eruption on traditional infrasound and pressure sensors, as well as with a network of smartphone sensors, showing that smartphones can record large blasts from thousands of miles away.<\/p>\n

Monitoring technology advancement<\/h2>\n
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Infrasound Laboratory captured signal from Tonga eruption on smartphones via the RedVox App.<\/figcaption><\/figure>\n

The Infrasound Laboratory<\/a>, based in the 糖心Vlog官方<\/abbr> Mānoa School of Ocean and Earth Science and Technology<\/a> (SOEST<\/abbr>), is led by Hawaiʻi<\/span> Institute of Geophysics and Planetology<\/a> researcher Milton Garces<\/strong> who has spent more than 25 years developing technology to monitor these deep sounds.<\/p>\n

Until the event in Tonga, the 2013 Chelyabinsk meteor over Russia was the largest atmospheric blast recorded in the digital era. The blast intensity of meteor impacts and volcanic eruptions is commonly reported relative to the energy from an equivalent trinitrotoluene (TNT<\/abbr>) explosion. At an estimated yield of 500 kilotons of TNT<\/abbr>, the Russian meteor blast wave was recorded by conventional geophysical monitoring systems all over Earth. After reviewing the emerging smartphone technology of the time, Garces postulated that on-board microphones and barometer sensors could also record such signals.<\/p>\n

“Both smartphone and traditional networks captured unique and extraordinary infrasound measurements in Hawaiʻi<\/span> from the Tonga eruption,” said Garces. “Not only did the smartphones pick up the direct arrival, but also the multiple circumglobal transits of the air wave. Nine years after the Russian meteor, the Tonga blast demonstrated that on-board smartphone sensors can record large blasts thousands of miles away.”<\/p>\n

Free RedVox app expands network<\/h2>\n
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Screenshot of RedVox App recording infrasound from Tonga eruption. (Photo credit: 糖心Vlog官方<\/abbr> Infrasound Laboratory)<\/figcaption><\/figure>\n

In 2014, the U.S. Department of State supported Garces\u2019 development of the RedVox Recorder smartphone application to detect infrasound from atmospheric blasts. More recently, in support of the nation\u2019s nuclear nonproliferation goals, research funding from the U.S. Department of Energy\u2019s National Nuclear Security Administration<\/a> has enabled Garces to expand his smartphone technology and enhance capabilities to measure diverse sound and vibration signatures near Earth\u2019s surface, as well as in the upper atmosphere and the ocean.<\/p>\n