Scientists say they have worked out why a small town in Hawaii has been hit by around 500 earthquakes a week.
Researchers say that Pahala on the island of Hawaii sits above an “interconnected feature” between 22 and 26 miles underground that is slowly swelling with molten rock, according to research published in Science.
Pahala has experienced swarms of earthquakes for decades. By 2015, the number had increased from around seven a week to 34.
Experts say that after the eruption of the Kilauea volcano on the island in 2018, the number dramatically shot up to hundreds per week -- around 192,000 in all.
Scientists say in their research that as pulses of magma, which is molten or semi-molten rock found deep beneath the Earth’s surface, enter the “sills” a string of earthquakes travel along their length.
“We were freaking out,” John Wilding, a graduate researcher at the California Institute of Technology and lead author of a study into the earthquakes, told National Geographic. “No one had ever directly observed magmatic activity at this scale before.”
The researchers used machine learning algorithms to dig through seismic data picked up by a network of sensors and found earthquakes so small they had previously been missed.
The quakes are located between the planet’s crust and core and reportedly so tiny that most of them are never felt on the surface.
Experts think that the town sits above a column of rock called a “hotspot” that helped build the Hawaiian islands, which have 15 volcanoes.
Kilauea, one of the world’s most active volcanoes, is erupting again earlier this month, creating lava fountains and lava “waves.”
Kilauea last erupted for 16 months starting in September 2021. For about two weeks starting last November, Hawaii had two volcanoes spewing lava side-by-side when Mauna Loa erupted for the first time in 38 years.