4.7 Part of the “Flock” Magnitude Earthquake in Western Australia


Western Australia (WA) experienced a magnitude 4.7 earthquake, the largest of the approximately 70 earthquakes recorded in the last three weeks.

However, experts say the cause of the flock is unknown and could be a larger event that is not out of the question in the near future.

“There is no good explanation for why herds occur,” said GA senior seismologist Tania Pejic. 6PR.. “So they aren’t really well understood.”

A 4.7-magnitude rumble was recorded 30 km (20 miles) west of Wagin early in the morning of January 25, but was felt about 230 km northwest of the state capital, Perth.

Wagin residents are reported to have awakened after the bed began to shake, with the roof wobbling and the windows rattling.

According to residents, tremors have been occurring continuously over the past few weeks. The region has already recorded 69 events, most of which are between magnitudes 2 and 3, with the first event occurring on January 5th.

Southwestern Western Australia is one of Australia’s most seismically active regions, but herds are rare and series of earthquakes usually occur only as aftershocks after a larger major event.

Epoch Times Photo
Map of important seismic events in Western Australia since 1906. (Gnangarra / Wikimedia Commons)

“What they are is a large number of earthquakes that occur in a short period of time without a major recognizable impact,” Pesic said.

“In the past week, we’ve recorded more than 30 earthquakes with a magnitude of about a few,” she said. “So far, this is the largest we have recorded and we have already recorded some aftershocks of this quake.”

Mr. Pesik said it is unclear if an earthquake with a recorded magnitude above 4.7 will occur in the future.

“Unfortunately, I don’t know. You can expect a peak in the flock … I can’t say anything about whether this will be followed by a small or large earthquake. It can happen. Is low, but that possibility cannot be completely ruled out, “she said.

The capture of the event was assisted by a new seismic recording station installed in 2020 after the 2018 Lake Muir seismic sequence.

In this case, there was a 5.7 earthquake on September 16, 2018. This is the largest quake recorded in southern Perth since the beginning of the record, occurring in southwestern Western Australia and parts of Perth.

Structures near the epicenter were damaged, and within the next two months 700 aftershocks were recorded, including magnitudes 4.6 and 5.4.

Daniel Kumerev

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Daniel Khmelev is a Perth-based Australian reporter working on energy, technology and politics. He holds a bachelor’s degree in mathematics, physics and computer science. Contact him at [email protected]