Mauna Loa and beyond: Reading of volcanic activity by recorded seismic waves

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Mauna Loa erupts for the first time since 1984 on the island of Hawaii on November 28, 2022 – Copyright BELTA/AFP/Archive Ramil NASIBULIN

A seismologist from Northwestern University – suzan van der lee – has been ‘looking inside the Earth’, focusing on the Mauna Loa eruption and what science can learn in terms of predicting future volcanic activity. Mauna Loa is one of the five volcanoes that make up the island of Hawaii in the US state of Hawaii in the Pacific Ocean.

Currently, Mauna Loa (the largest active volcano in the world) is erupting for the first time since 1984, as reported by the BBC. The report indicates that lava flows down the side of the volcano at a temperature of 1,000 degrees Celsius. This brings with it the additional risks of ash fallout and destructive earthquakes.

While ash is a problem, what researchers are most interested in is the amount of lava. Van der Lee says: “Each volcano is unique. Hawaiian volcanoes are not known for the amount of ash they spew. It is mainly lava, which flows gently. It is not a very violent erupting volcano. Although there was originally an advisory for ash, which can affect lungs, crops, and water supplies, it appears that most of the danger to people living on the edge of the island of Hawaii at lower elevations was the potential lava flow”.

One of the reasons researchers are aware of Mauna Loa’s distinctive features is based on advances with tracking systems. Technology has made it possible to improve predictions and communication about the eruption of Mauna Loa.

Van der Lee explains in a statement sent to Digital magazine: “Since a trip inside the Earth is not physically possible, we use data and technology, for example, recorded seismic waves to see what is happening inside the Earth. It is as amazing that we can look inside the Earth as we can look inside a human body with an MRI.” Through technology it is possible to create tomographic images (images that use seismic waves to virtually section the interior of the Earth).

A key means of monitoring is by using seismometers, installed around the island to collect a growing activity. This reveals considerable detail because as magma speeds its way to the surface, it needs to break through solid rock. That creates seismic waves that are recorded and tremors.

According to Van der Lee: “That is a very important observational tool. Other ways are geodetic instruments, such as Global Navigation Satellite Systems (GNSS) tilt gauges, which constantly measure the shape of volcanoes. If that shape expands to the left, right, or up, that could be an indication that something is going on below and trying to make room for magma to rise to the surface. Other instruments measure gases that routinely escape through fissures, cracks, vents, etc.

These approaches have been used in other parts of the world. For example, assessing a volcanic island in Tonga that erupted in a very unusual and uncharacteristic way. Van der Lee’s research on observed seismic waves helps researchers better understand volcanoes and gain insight into the structure of Earth’s interior.

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