FW: Geophysics Weekly Meeting (Season 2026/1, Episode 7) [SEC=OFFICIAL]

[Trevor Allen]

Howdy folks – I’m not normally one for gratuitous self-promotion, but just thought I’d advertise this presentation that I’m giving at ANU Research School of Earth Sciences tomorrow.  To de-jargon the word salad below, I’m effectively looking at alternative methods for characterising ground-motions for future seismic hazard assessments on AU.  Feel free to join online.

 

Trev

 

PS – I believe Item 1 on the agenda pertains to a short student presentation on recent seismicity, so it may not be critical to join right at 11.

 

 

From: Carl Martin <Carl....@anu.edu.au>
Sent: Wednesday, 25 March 2026 3:54 PM
To: 'RSES All' <rses...@anu.edu.au>
Subject: Geophysics Weekly Meeting (Season 2026/1, Episode 7)

 

Hi all,

 

Buckle your seat belts and get ready for our exciting Geophysics Weekly Meeting mid-season finale*. This week's meeting features guest speaker Dr Trevor Allen, a Senior Seismologist at Geoscience Australia. More details below:

 

1. Seismicity — Miriam Gauntlett

 

2. Research talk — Dr Trevor Allen (Geoscience Australia)

Regionalisation of Earthquake Source and Attenuation Characteristics for Continental Australia

 

Abstract: Characterising the source properties of earthquakes and exploring the attenuation of earthquake ground motions are of critical importance to seismic-hazard assessments. Australia possesses some source and ground-motion characteristics that are largely unique to the continent. This means that it is difficult to simply use “off-the-shelf” ground-motion models from tectonically analogous regions. Using a new ergodic continental-scale Fourier spectral attenuation model, source parameters—specifically, moment magnitudes (MW) and stress drops (Δσ)—are derived for well-recorded earthquakes occurring within Australian continental crust since 1994. Inter-event residuals of Fourier amplitude spectra are subsequently calculated relative to the ergodic ground-motion attenuation model. The study finds that consideration of an earthquake’s stress drop as a ground-motion predictor variable can lead to significant reductions in the standard deviation of the inter-event ground-motion residuals (τ) relative to the ergodic model. Using this observation, the k-means unsupervised machine learning clustering technique is used to group earthquakes in similar geographical locations (longitude and latitude), regulated by similarities in stress drop. The study investigates whether the use of a priori cluster-based inter-event correction terms—based on the mean stress drop for the cluster—can be used to minimize τ. The results of this partially non-ergodic case demonstrate that significant reductions in τ can be achieved through the use of cluster-based corrections. This information can be used for the development regionally adjusted ground-motion attenuation models that consider regional earthquake source characteristics within continental Australia. 

 

As usual, we'll be in the J1 Seminar Room at 11 on Friday (27th March).

 

For anyone who can't attend in person, you can join the meeting via Zoom: https://anu.zoom.us/j/84848321329?pwd=bbvHLtJcrkxKlUrdWrh9OubcnOkpDH.1 (password = rses).

 

Geophysical greetings 🌏

Carl & Ammu

 

*Note: there is no GWM next week due to the Good Friday public holiday.

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[Mark Quigley]

Thanks Trev – I will try to join.

Mark

 

From: aee...@googlegroups.com <aee...@googlegroups.com> On Behalf Of Trevor Allen
Sent: Thursday, 26 March 2026 12:19 PM
To: 'Adam Pascale' via aeesorg <aee...@googlegroups.com>
Subject: [EXT] [aees] FW: Geophysics Weekly Meeting (Season 2026/1, Episode 7) [SEC=OFFICIAL]

 

External email: Please exercise caution

 

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