Tremors still felt

ONGOING earth tremors being felt across the Latrobe Valley can be expected to continue for months, according to a leading Victorian seismologist.

Environmental Systems and Services head of seismology Adam Pascale said while there may have only been a handful of aftershocks felt by some residents, there had already been “hundreds” recorded since the 19 June 5.4 magnitude earthquake.

“While the larger aftershocks have been around the 2.5 and 3 magnitude range, we’ve had a lot more (shocks) than people have felt; maybe only people at epicentre would feel the smaller ones,” Mr Pascale said.

Express reader and Morwell resident Rosemary Twyerould reported on Facebook she was still feeling aftershocks last week, likening the experience to going “over a speed bump”.

Mr Pascale said with the entire Gippsland region positioned well within Australia’s tectonic plate boundaries, a fault line of up to 15 kilometres beneath Moe had become a weak link, and buckled under years of pressure from plate movement.

“While the earthquake released that pressure, it starts building up again, and each of those aftershocks are part of an ongoing cycle in which pressure builds and releases,” Ms Pascale said.

“This will continue until the rock is in a state that it can start building up long-term stress again bear in mind we are still having aftershocks being felt (in South Gippsland) as a result of the (July 2011) Korumburra earthquake.”

Mr Pascale said while the scale and rate of Moe aftershocks have “died off quicker” compared to recent earth movement events in the area, such as the Baw Baw magnitude five earthquake in 1996, for which ESS was still recording movement, current tremors “could be a precursor of a larger event” to come.

“Months after the initial Korumburra earthquake, we had two (magnitude) 4.5s within three weeks of each other, which larger than the original, became considered the main events,” he said. “The Moe earthquake has been good cause people get into the habit that we do actually have earthquakes in Australia.”