Melbourne’s earthquake: magnitude, intensity and building response

A few days ago, I was following news of the earthquake in Kunming, back home in Yunnan Province of China. Early this morning, Victoria—where I now live—had one too.

At the time, I was still working late, reviewing engineering drawings and calculations.

Growing up in Yunnan, earthquakes were familiar to me. I later studied civil engineering, and seismic design became an important part of my professional work. That experience continues to inform my structural design, forensic investigations and remedial work here in Australia. Construction practices differ, but the underlying physics remains the same.

Geoscience Australia reported the following for this morning’s earthquake:

• Time: 3 October 2026, 2:01:39 am AEST
• Magnitude: 4.8 (MLa)
• Depth: 10 km
• Epicentre: near Leongatha, approximately 100 km southeast of Melbourne’s CBD
• Felt reports: 21,142 at the time of the screenshot

Reading GA’s published ShakeMap, Version 5, the estimated shaking around central Melbourne was approximately Modified Mercalli Intensity (MMI) IV—classified as “light”—with variation across Greater Melbourne.

“Light” does not mean unnoticeable. At this intensity, people indoors may clearly feel the shaking, windows and dishes may rattle, and some people may wake up.

The map estimates ground shaking across an area. What someone feels on a particular floor also depends on the building’s response. Being shaken awake does not, by itself, establish that a building has suffered structural damage.

I’ve attached GA’s event details and official intensity map for reference. The map uses UTC: 2 October at 16:01 corresponds to 3 October at 2:01 am here in Melbourne.

#EarthquakeEngineering #StructuralEngineering #SeismicDesign #Melbourne #GeoscienceAustralia