Large rockfall in NSW recorded on SAA seismograph

Ask Roz Blue Mountains 

August 2 at 5:00 PM  

LANDSLIDE in the Grose Valley. Today, Ian Smith noticed a significant new landslide on the northern wall from Evans Lookout, Blackheath.

 

SRC detected a signal that rumbled for about a minute at 1:05am (morning of August 2nd) across multiple seismographs in Sydney’s west. Definitely not an earthquake signature, so quite possibly this rockfall.

SAA’s Eric Wang posted:

Something a bit different than usual today. A rockfall occurred sometime last week around Evans Lookout, Blackheath in the Blue Mountains.

Adam Pascale from the Seismology Research Centre managed to pick up a seismic signal from the SRC’s nearby seismometers. One of our stations (HAZO) has a clear spike in the waveform at the same time Adam recorded it on his network. Below you can see the signal (green trace) at around 15:05 UTC or 1:05am EST on the 2nd August , lasting about a minute. A spectrogram below the trace indicates the energy release as a function of time.

More information from Adam can be found in this Linkedin post: https://www.linkedin.com/posts/adam-pascale_forensic-seismology-activity-7359042118444568576-N-rG?utm_source=share&utm_medium=member_android&rcm=ACoAADJ_egkBBn5c9YtcU_43jD-11G8MqBy-n-U.