Moderate Earthquake (M4.7) Reported Near 98 km S of Encounter Bay, Australia

A seismic event measuring magnitude 4.7 has been recorded by global monitoring networks, with the epicentre located 98 km S of Encounter Bay, Australia. The earthquake occurred at 21:18 UTC on Monday, October 26, 2026 and was detected at a focal depth of 10.0 km.

Seismological Overview

Earthquakes are the result of sudden energy release in Earth's crust, most commonly along fault lines where tectonic plates interact. This energy radiates outward as seismic waves — measured and characterised by networks of seismographs operated by agencies including the USGS, JMA, EMSC, and GFZ.

Australia sits in the interior of the Indo-Australian Plate, far from active plate boundaries. While considered a stable continent, it experiences moderate intraplate seismicity — and because its population is concentrated along the coast, even moderate earthquakes can affect large numbers of people.

Event Parameters in Detail

Magnitude: 4.7 (moment magnitude scale, Mw) — a moderate earthquake.
Depth: 10.0 km
Location: 98 km S of Encounter Bay, Australia
Time: 21:18 UTC on Monday, October 26, 2026

At a focal depth of 10.0 km, this is classified as a shallow earthquake (0–70 km). Shallow events are typically the most damaging: the seismic energy has less distance to travel before reaching the surface, resulting in stronger and more abrupt ground shaking at the epicentre.

Energy and Ground Motion

A magnitude 4.7 earthquake releases approximately roughly 500 tonnes of TNT of energy. For comparison, this exceeds the energy released by most conventional explosive events and is sufficient to shift tectonic stress in measurable ways across a wide region.

Moderate earthquakes are felt by virtually everyone near the epicentre. Strong shaking lasting 10–30 seconds can topple unsecured items, crack plaster, and cause poorly anchored objects to fall. Aftershocks are common following moderate events.

Significant damage can occur to vulnerable structures — particularly unreinforced masonry, old adobe buildings, and poorly maintained older construction. Well-engineered modern buildings are designed to withstand this level of shaking with minimal structural impact, though contents may shift and non-structural elements (ceilings, partitions) can be damaged.

Regional Seismic History

Australia's largest recorded earthquake was the 1988 Tennant Creek sequence (M6.7–6.8) in the Northern Territory. More recently, the 2016 Petermann Ranges earthquake (M6.1) produced a dramatic surface rupture. Historical underestimation of Australian seismic hazard has been revised upward as geological research uncovers evidence of prehistoric large earthquakes.

Public Safety Guidance

For residents in the affected area, the immediate priority is assessing personal safety and structural integrity. Understanding the type of building you live or work in is one of the most important steps in earthquake preparedness. Older unreinforced masonry buildings and soft-storey apartment buildings are significantly more vulnerable than modern reinforced concrete or steel-frame structures. If you have concerns, consult a structural engineer.

The internationally recommended action during earthquake shaking is Drop, Cover, and Hold On: drop to your hands and knees, take cover under a sturdy table or desk (or protect your head with your arms if no shelter is available), and hold on until shaking stops. Do not run outside during shaking — most injuries occur when people attempt to move.

Geoscience Australia monitors seismic activity nationwide. Given Australia's relatively low frequency of damaging earthquakes, public earthquake preparedness awareness is an ongoing priority.

Continued Monitoring

The USGS and regional seismic networks will continue to monitor this event for aftershock activity. QuakeWatch aggregates this global data in real time — you can view all current seismic activity on our live map, or explore our earthquake science guides to learn more about the forces behind events like this one.