USGS: “A USGS geophysicist measures contact resistance on electrodes at a temporary magnetotelluric site.” (USGS photo by M. Cappos)

(BIVN) – Scientists are conducting magnetotelluric sounding on Kīlauea this month, in order to image structure and fluids beneath the surface of the Hawaiʻi island volcano.

Kīlauea is not erupting and has been quiet ever since the previous eruption paused on June 19th, 2023. The USGS Alert Level for the volcano is ADVISORY.

Photos published to the USGS website show scientists deploying and checking magnetometers at various sites around Hawaiʻi Volcanoes National Park. The electrodes and wire coils are buried at shallow depths, and measure the electromagnetic energy, or EM, generated by lightning strikes around the equator.

The project is now in its second season. A USGS Volcano Watch article published in May 2022 described the project before the first season got underway, saying:

The technique is called magnetotelluric (MT) sounding. Lightning storms are common in equatorial regions and those storms produce surprisingly constant electromagnetic noise that travels around the globe in the atmosphere between the Earth’s surface and the ionosphere.

The response of the earth to this distant EM stimulation can tell us the electrical properties of the earth below the coils to depths of about 10 km (6 mi). The one-square-meter (yard) setup will be moved to about 125 ground locations on the volcano. The resulting data will be used to develop a detailed picture of Kīlauea’s inner workings. 

The USGS says the electrodes, induction-coil magnetometers, and data loggers are deployed for about a month at each location.

The Hawaiian Volcano Observatory says a “comparison to similar datasets collected prior to the 2018 lower East Rift Zone eruption and summit collapse of Kīlauea will highlight any changes.”

“The project is funded by the Additional Supplemental Appropriations for Disaster Relief Act of 2019 (H.R. 2157), which provided the USGS HVO with funds to conduct scientific investigations of the current state of Kīlauea,” the USGS added. “This project has been permitted by Hawai‘i Volcanoes National Park.”