Updated: 18th August 2025
Saturday 16th August 2025 – A rare and significant earthquake measuring 5.6 on the Richter scale struck near Kilkivan in Wrattens National Park at 9:49 AM, sending tremors across southeast Queensland and giving Blackall Range residents a dramatic wake-up call.
The earthquake, which occurred at a depth of approximately 10 kilometres, was felt as far away as Brisbane and represents the largest onshore Queensland earthquake in more than 50 years, according to Dr Michelle Salmon from Geoscience Australia.
“This is significant in the context of Australia,” Dr Salmon confirmed. The earthquake’s importance is underscored by Geoscience Australia’s emergency protocols: “This size event is one of the reasons we have a 10-minute requirement to get information out so interstate emergency services know what’s going on.”
Local Impact and Community Response
Residents across the Blackall Range experienced intense shaking that lasted between 7-15 seconds, depending on location and geological conditions. The earthquake’s effects were particularly noticeable given its shallow depth and the region’s hard volcanic bedrock.
A local resident described the experience: “I was in the kitchen when things started moving across the table. We had crockery rattling, floor vibrations, all the pictures in the house were crooked, and the pets were clearly distressed. Our neighbours noticed their trees were shaking.”
The intensity of shaking experienced across the Blackall Range registered between IV and V on the Modified Mercalli scale, according to Dr Salmon. “Five is your dishes rattling, your walls creak and your windows rattle, and five is trees and bushes shaking noticeably,” she explained.
Swift Detection and Response
Geoscience Australia’s monitoring network detected and reported the earthquake within the required timeframe, despite the nearest seismometer being located as far away as Brisbane. Dr Salmon explained how the agency uses multiple stations including those in Toowoomba, Eidsvold, and Rhinelow to triangulate earthquake locations.
The earthquake generated an unprecedented community response, with Dr Salmon reporting that “the total number at the moment is 23,870” felt reports submitted to Geoscience Australia—a remarkable figure that demonstrates both the earthquake’s widespread impact and community engagement.
Infrastructure Impact
The earthquake caused some localised disruption across the region. Several areas experienced temporary power outages, with Energex crews working throughout Saturday morning to restore electricity to affected communities. Queensland Rail temporarily suspended services on the North Coast Line as a precautionary measure whilst conducting safety inspections of tracks and bridges between Brisbane and Gympie. Brisbane to Gold Coast services were temporarily disrupted. Minor structural damage was reported in some areas.
Geological Context and Why the Shaking Was So Widespread
The earthquake’s location in Wrattens National Park, likely “between Mount Mia and Black Snake,”, sits within Queensland’s volcanic terrain. The regional geology and volcanic origins of the Blackall Range and surrounding Sunshine Coast area had a major influence on how earthquake waves travelled and how intense the shaking felt across nearby communities.
Hard Volcanic Bedrock Foundation Much of the Blackall Range sits atop ancient volcanic rocks, including basalts and hard lavas. These dense, rigid rocks transmit seismic waves very efficiently with minimal energy loss compared to softer, sedimentary layers. As Dr Salmon explained, “Basalt is actually extremely hard rock, so it will shake at high frequencies more, but also it’s not as likely to amplify the seismic waves.” The result is that “it’s a bit like a telephone wire” in how the hard rock carries earthquake waves over greater distances.
This geological foundation explains why shaking was both intense and widespread, with seismic energy travelling farther and faster than it would through softer rocks. Even towns some distance from the epicentre experienced significant tremors because they’re built on or near these efficient wave-transmitting volcanic rocks.
Complex Wave Behaviour The varied geological landscape created complex shaking patterns across the region. Wherever the bedrock changes—from hard lava to softer sediments—seismic waves reflect and refract, causing wave amplification in some locations and more complex, rolling motion as waves convert and scatter at geological boundaries.
In areas where soft soils or sediments cap the volcanic bedrock, these surface layers can amplify shaking further, particularly if they’re loose or waterlogged. This helps explain why residents reported such varied experiences: people atop solid volcanic rock felt a more abrupt, “snappy” shaking, while those over softer ground experienced longer or more rolling motion.
Local Variations in Shaking The presence of old volcanic features—including cracks, ancient lava flows, and fault systems—can direct or magnify shaking in certain valleys and ridges. This geological complexity meant that even neighbouring properties could experience noticeably different intensities of shaking, depending on their specific geological foundations.
The fault movement responsible for the earthquake appears to be “a compressive fault of some kind,” likely a reverse fault caused by “forces coming in from sort of the east and the west,” according to Dr Salmon. Importantly, she noted that “we have no faults actually mapped” in the immediate area, though this isn’t unusual for Australia where many faults lie hidden beneath sediment or have been eroded away.
Why This Earthquake Felt So Strong The volcanic origins make the Blackall Range region particularly susceptible to strong, efficiently transmitted shaking, as seismic energy travels easily through the tough, dense rocks. This geological reality explains why Saturday’s shallow earthquake—despite being of moderate magnitude—felt unusually strong and was noticed across such a wide area, from the immediate epicentral region all the way to Brisbane.
Broader Tectonic Context
This earthquake fits within Australia’s broader tectonic framework. “It will be associated with the stress regime across Australia,” Dr Salmon confirmed. “The forces are originally coming from the tectonic plates around Australia, and the stresses travel inland.” Despite this connection to continental-scale forces, the Blackall Range and Sunshine Coast region is not considered earthquake-prone. “Most of Queensland is considered a low seismic hazard area in Australia,” Dr Salmon emphasised, making this event all the more significant for local communities.
The Science Behind the Shaking
The distinctive rumbling sound reported by many residents has a scientific explanation. “Often the rumbling is actually the sound that the earthquake waves are themselves making if you’re close to the event,” Dr Salmon explained, though it can also be caused by rockfalls and objects rattling.
The variation in perceived duration—from seven to fifteen seconds reported by different residents—reflects both the physics of seismic waves and human perception. Dr Salmon explained that earthquakes feel different depending on distance from the epicentre: “As you get further away, the seismic waves spread out a bit. You’ll get longer shaking the further you go away,” while acknowledging that “people’s perception of time is not particularly good” during such events.
Aftershocks and Ongoing Monitoring
Several small aftershocks have been recorded since the main event, though Dr Salmon noted that “there’s not a lot that we’ve recorded so far” due to their small size and the distance to monitoring equipment.
Geoscience Australia is deploying additional seismic monitoring equipment to the region to better understand the earthquake’s characteristics. Dr Salmon explained. “It gives us a better understanding of the depth of the earthquake, the size of the fault that has actually broken.”
This additional monitoring will also provide accelerometer data to complement the felt reports from residents. “Rather than the reports from people, we will get accelerometers in the area, so they’ll actually be measuring that shaking themselves,” Dr Salmon noted.
Community Preparedness
The earthquake serves as an important reminder for Australian communities about earthquake preparedness. “One of the issues with Australia is because the earthquakes are few and far between, people aren’t necessarily prepared for them,” Dr Salmon observed. “We know this is a really good warning that we can actually get significant earthquakes in Australia.”
Geoscience Australia’s standard earthquake safety advice remains: “Drop to the ground, so you don’t fall over. Get underneath something that’s sturdy and hold on so it doesn’t shake away from you.”
Historical Significance
To put this event in perspective, Dr Salmon confirmed this was “the largest onshore Queensland earthquake for more than 50 years.” While Australia experiences magnitude 5+ earthquakes roughly every 5-10 years, they are typically isolated events, making this earthquake particularly significant for Queensland and the broader Australian seismic record.
Looking Forward
The wealth of felt reports and the planned additional monitoring will contribute valuable data to Australia’s seismic hazard mapping. “It builds into the national safety, basically,” Dr Salmon explained, ” this information helps engineers determine building standards”.
For Blackall Range residents, this earthquake represents both a reminder of the geological forces at work beneath our feet. The swift response from emergency services, the remarkable community engagement through felt reports, and the rapid scientific analysis all demonstrate how well-prepared we can be when nature reminds us of its power.
Community members who experienced the earthquake are still encouraged to submit their felt reports to Geoscience Australia’s website, as this information contributes valuable data for ongoing research and safety planning.
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