UPDATED TUESDAY: SECOND LARGE EARTHQUAKE ON SATURDAY – Mt Arthur, Muswellbrook near Denman, Hunter Valley Earthquake

23 August 2024

Day 5: Tuesday 27th August 2024

On Tuesday 27/8/2024 there was an aftershock measuring 2.8
More siesmic sensors are being installed in the Hunter Valley to determine the cause and a more accurate location of each quake.

Latest Earthquake List

Created by Karen Adnum

Day 4: Monday 26th August 2024

On Monday evening at 9:15pm there was an aftershock with a magnitude of 2.9. The epicentre is located South East of the Mt Arthur coal mine.

Day 3: Sunday 25th August 2024

There was a strong aftershock at 12:11am measuring 3.2 early on Sunday morning, see image below
There was another aftershock at 1:03am measuring 2.46
There was another aftershock at 1:19am measuring 2.55
There was another aftershock at 3:12am which measured at 2.3 magnitude
There was another aftershock at 8:31am which measured 2.33
There was another aftershock at 4:59pm which measured at 2.5 magnitude
There was another aftershock at 7:38pm which measured at 2.4 magnitude
There was another aftershock at 8:41pm measuring 2.48 magnitude
There was another aftershock at 9:15pm measuring 3.0

The large red dot indicates the location of the 12:11am aftershock on Sunday morning.

The Hunter Valley has been rattled by a series of significant earthquakes over the last few days, bringing renewed attention to the region’s vulnerability to seismic activity. Muswellbrook and surrounding areas have experienced several tremors, with the strongest recorded at a magnitude of 4.7. These quakes have been felt across the region, including in Newcastle and even as far as Sydney, Port Macquarie and even Wollongong raising concerns among residents.

The first major quake struck on Friday, followed by a series of aftershocks that have continued into the weekend. Early Sunday morning, the region was shaken by another strong tremor, adding to the unease in the community. The ongoing seismic activity has led to the temporary closure of schools, businesses, and public services in some areas. Geoscientists have warned that aftershocks are likely to continue, although they are expected to decrease in intensity over time.

Bricks fallen into laneway in Muswellbrook — Bricks fell on to a laneway in Muswellbrook on Friday.

The Geology Behind the Earthquakes

The Hunter Valley sits within the broader Sydney-Gunnedah-Bowen Basin, a significant geological formation stretching from southern New South Wales to central Queensland. While the Hunter Valley itself is not technically within the Sydney Basin, it is part of this larger geological structure. The region is heavily influenced by the Hunter-Mooki Thrust Fault System, a major fault line that runs through the area and contributes to the seismic activity.

Over time, tectonic forces cause stress to build up along this fault line. When the pressure becomes too great, it’s released in the form of an earthquake. The region’s history of seismic activity, including the infamous 1989 Newcastle earthquake, highlights the ongoing risks. That event, which reached a magnitude of 5.6, caused widespread destruction and is still fresh in the minds of locals.

The Hunter Valley has experienced other significant seismic events, such as the 1925 Maitland earthquake. These events show that the area is susceptible to ongoing geological tension and the sudden release of energy that leads to earthquakes.

Items fell from shelves in shops around the region.

Day 2: Saturday 24th August 2024

A second strong earthquake has been recorded at the Mt Arthur Coal Mine, at Muswellbrook earlier today, it was of similar in magnitude to yesterday’s earthquake and the epicentre was located in the same location.

Here’s a summary of what happened on day 2 (scroll down for Friday night’s details):

There was an aftershock at Edderton at 9:13am measuring 2.6
Another aftershock at 1:06pm measuring 2.7
Yet another at 3:56pm measuring 2.5
Geoscience Australia recorded a second, strong earthquake at 4:31pm Saturday with a magnitude of 4.7 which was felt in Newcastle and Sydney
Shortly after, at 4:43pm, a further aftershock measuring 2.7 was recorded.
Then at 5:33pm there was another aftershock measuring 2.6
Then an aftershock at 10:57pm at 2.6

Reports indicate the tremors were felt across Newcastle, the Hunter Valley, and as far as Sydney.

There have been a total of 11 tremors recorded since yesterday and it is expected that there could be more to come, authorities can not predict how many more there will be, but Dr Hadi Ghasemi from Geoscience Australia said that the stronger aftershocks usually happen early on, meaning they could decrease in intensity as time goes on.

The first earthquake yesterday closed down schools, businesses and government organisations and caused a lot of damage in Muswellbrook.

Each dot represents one earthquake or aftershock. The red dots are the most recent.

NSW Police released an official statement at 7:00pm Saturday

[NSW Police] Emergency services alerted to earthquake near Muswellbrook
Saturday, 24 August 2024 07:00:27 PM

NSW Police and other emergency services have been alerted to an earthquake in the Hunter Valley today (Saturday 24 August 2024).

The earthquake recorded a magnitude of 4.7 at 4.31pm near Muswellbrook.

Officers from Hunter Valley Police District have not been made aware of injury or damage to infrastructure.

Residents are advised to alert their local relevant authorities of any injury or damage.

Reports of a WATER OUTAGE in Muswellbrook Following Second Earthquake On Saturday

Reports indicate a water outage in Muswellbrook. The posts also mention a power outage; however, I couldn’t verify any details about the power issue, so it’s likely that power has already been restored.

Residents have had enough, this was posted on Saturday

A Bulletin has been released confirming there is no Tsunami threat for second earthquake on Saturday

Official Details Of Large Earthquake 4:31pm Saturday:

Official Details Of Aftershock at 4:43pm Saturday:

Graphic Posted By Seismology Research Centre on X for Saturday’s Earthquake

Another Graphic Posted EMSC on X For Second Earthquake on Saturday

This one shows you topography of the area.

Another Graphic Posted By Prof Ray Willis Following Second Large Quake on Saturday.

It appears to show rock composition or plates in the area.

This graphic is from AusQuake, from the second earthquake on Saturday

It shows the intensity detected at each testing site from their network.

LAST NIGHT (Overnight)

A TIMELINE OF OVERNIGHT AFTERSHOCKS

1:10am Saturday – A Newy 87.8 reporter was woken up by a creepy wave-like sensation at Newcastle West

In his Google history, you can see he was desperately trying to find the cause at 1:11am, this matches up with the first official GA report below (scroll down)

1:10am Saturday – Geoscience Australia have reported and confirmed a 3.2 magnitude earthquake at Muswellbrook (small red dot)

And it was detected by the following seismic stations:

This graphic shows the 3.5 magnitude aftershock was detected by seismic stations as far as Canberra.

2:26am Saturday – Geoscience Australia have reported and confirmed a 2.5 magnitude earthquake / aftershock

And it was detected by the following seismic stations:

This graphic shows the 2.5 magnitude aftershock was detected by seismic stations as far as Canberra.

4:57am Saturday – Geoscience Australia have reported and confirmed a third 2.5 magnitude earthquake / aftershock

And it was detected by the following seismic stations:

In addition to the 3 aftershocks overnight, there was a fourth aftershock fifteen minutes after the main quake yesterday.

Please be aware that aftershocks after a large earthquake are common and expected, and they may last for days or sometimes weeks after the main earthquake.

Day 1: Original Report – Friday 23/8/2024

A magnitude 4.7 earthquake struck New South Wales at midday today, with tremors felt across large parts of the state. Geoscience Australia (GA) reported the epicentre to be located in the Wollemi National Park, near Denman in the Upper Hunter Valley, approximately 14 kilometres east of the town.

The tremor, which occurred at a depth of 10 kilometres, sent shockwaves through various regions, including the Upper and Lower Hunter, Central Coast, Lake Macquarie, Dubbo, and even as far as Sydney and Port Stephens.

Widespread Reports of Shaking

Residents took to social media almost immediately, sharing their experiences of the quake. Many described their homes shaking, with furniture moving and windows rattling. In Muswellbrook, some locals reported items falling off shelves, and minor aftershocks were noted in the area. Lavis Mitre 10 in Muswellbrook shared an image showing aisles disrupted by the tremor with products scattered on the floor.

Power Outages

Muswellbrook Blackout — Muswellbrook Is Blacked Out

The South side of Muswellbrook is reporting a large scale power outage following the earthquake affecting 2506 premises. Ausgrid have acknlowedged this and have crews on scene to find the source of the outage and to ensure the network is safe before re-energising the network.

Regional Impact

Residents in Newcastle, Mudgee, Gulgong, and Anna Bay also felt the tremor, with some mistaking it for heavy construction or a passing truck. “Rattled the things on my table at Swansea Heads,” said one local, while another in Muswellbrook mentioned feeling two aftershocks and experiencing power outages in parts of the town.

In Sydney, reports of shaking in high-rise buildings surfaced, with some residents posting on social media about the unsettling experience. “My apartment just moved… who else felt it in Sydney?!” one user wrote.

A man in Mascot told Newy 87.8 that the movement was significant, it moved his office chair and it felt like a “wobble”.

Official Response and Safety

NSW Police and NSW Health confirmed that, fortunately, there have been no reports of injuries resulting from the earthquake. The Bureau of Meteorology confirmed there is no tsunami threat following the event.

Geoscience Australia continues to monitor the situation, and authorities are advising people to remain alert for any potential aftershocks.

Understanding the Risk of Aftershocks Following an Earthquake

After a significant earthquake, like the recent 4.7 magnitude tremor near Denman, there’s always a risk of aftershocks. These are smaller earthquakes that follow the main event as the earth’s crust adjusts to the new position caused by the initial quake. Aftershocks can happen minutes, hours, or even days after the main earthquake, and while they’re usually less intense, they can still cause additional damage—especially to already weakened structures.

Aftershocks occur because the energy released by the main quake is not always fully dissipated, leading to continued movement along the fault lines. The size and frequency of aftershocks typically decrease over time, but it’s not uncommon for some to be felt strongly, particularly in areas near the original epicentre.

Residents in the affected areas are advised to stay alert and be cautious of possible aftershocks. Following safety protocols, such as checking buildings for damage and having an emergency plan in place, is essential during this period of heightened seismic activity.

Coal Mine Not The Cause

While some speculation arose about whether the nearby Bengalla coal mine could be responsible for the recent earthquake near Denman, the magnitude and depth of the tremor indicate that it is more likely due to natural tectonic activity rather than mining operations. Typically, seismic events directly linked to mining are minor and localized, often caused by controlled blasting or subsurface collapses. However, a 4.7 magnitude quake suggests deeper tectonic forces at play rather than any human activity at the coal mine

The Project Leaves Facebook Users Annoyed After Graphic Highlights Earthquake Was In Sydney

In a classic case of “Nothing exists outside of Sydney”, The Project reported that the 4.7 magnitude earthquake that shook parts of New South Wales was in Sydney. The reality? The quake was far from Sydney, with its epicentre near Denman in the Upper Hunter Valley, about 255 kilometres away however it was felt in Sydney.

Social media quickly lit up with locals from the Hunter Valley and beyond expressing frustration over Sydney being wrongly labelled as the epicentre. Comments like “Not everything is about Sydney” and “Some media outlets haven’t worked out there is anywhere in NSW except Sydney” captured the sentiment of many who were quick to correct the misinformation.

Newcastle radio station Newy 87.8 FM posted: “The earthquake was in Denman, not Sydney,” highlighting the regional focus of the tremor. Another commenter quipped, “Poor Sydney, wants to be the centre of attention again. It wasn’t even in Sydney, you morons!”

Even as residents in Sydney felt the tremor, the insistence that the quake occurred in their city has caused frustration among those in the affected regions. One Muswellbrook resident said, “It started in Muswellbrook and knocked the power out in a large scale. It’s always about Sydney, isn’t it?”

While it’s understandable that the tremor was felt in Sydney, the true impact was centred in the Hunter Valley, where residents experienced significant shaking, with some reporting minor property damage. As one commenter humorously put it, “Sydney, stop claiming our stuff!”

Comparing the Denman Earthquake to the Devastating 1989 Newcastle Earthquake

While the recent 4.7 magnitude earthquake near Denman caused widespread tremors, it pales in comparison to the infamous 1989 Newcastle earthquake. The Newcastle quake, measuring 5.6 in magnitude, struck much closer to a densely populated area, leading to significant damage and loss of life.

The Newcastle earthquake remains one of Australia’s most catastrophic natural disasters, causing 13 fatalities, hundreds of injuries, and extensive destruction across the city. Buildings collapsed, roads buckled, and the damage bill exceeded $4 billion. Its proximity to the city meant that the urban infrastructure and densely packed communities bore the brunt of the quake, amplifying its impact.

In contrast, the Denman quake, though felt across a wide area, was centred in a less populated region. While tremors reached as far as Sydney, Newcastle, and the Central Coast, the physical damage was minimal compared to what Newcastle endured in 1989. The geographical distance from major urban centres helped mitigate the potential devastation, but it’s a stark reminder of the vulnerability of cities near fault lines.

The 1989 event remains a touchstone for understanding the impact of earthquakes in Australia and highlights why preparedness is critical, especially in more urbanised areas.

Hunter Valley Earthquake Raises Concerns About Proposed Nuclear Power Plant at Liddell

Liddell Power Station

The recent 4.7 magnitude earthquake near Denman, which shook large parts of the Hunter Valley, has sparked concerns about the location of a proposed nuclear reactor at the nearby Liddell power station site. The proposal, part of a broader plan by the federal Coalition, aims to repurpose the former coal-fired power station into a nuclear energy hub by the 2030s. This plan has been met with mixed reactions, especially in light of the seismic activity in the region.

Liddell, located just 35 kilometres from Denman and close to Muswellbrook, is one of seven sites identified for potential nuclear reactors. The proximity of this earthquake to the proposed site has fueled discussions about the safety and feasibility of building a nuclear facility in an area prone to tremors. Residents are questioning whether the region’s geology can support such a project without risking public safety.

Countries like Japan have significant experience running nuclear facilities in earthquake-prone regions, which provides valuable insights into how Australia might manage similar risks at the proposed Liddell nuclear site. Japan’s nuclear reactors are designed with rigorous safety measures to withstand seismic activity. These include constructing reactors on robust foundations that are less likely to amplify ground vibrations, using detailed geological assessments to predict and design for the maximum potential earthquake, and implementing automatic shutdown systems that activate when strong seismic motion is detected.

For example, Japanese plants incorporate large-scale shaking tests to validate the safety of critical infrastructure against earthquakes that exceed design assumptions. In the wake of the Fukushima disaster, Japan significantly strengthened its regulatory standards, focusing on deep geological investigations, defense-in-depth strategies, and upgrading protections against natural disasters like earthquakes and tsunamis.

The country’s approach emphasises building on stable ground, reinforcing structures, and improving early detection systems that can shut down plants before damage occurs. This combination of advanced design, rigorous testing, and enhanced safety regulations has allowed Japan to operate nuclear plants safely in seismically active areas.

These lessons could be crucial as Australia considers building a nuclear plant at Liddell, a location not far from the recent Denman earthquake. While such a facility would bring new energy opportunities, it would also require stringent seismic safety planning to ensure it can withstand any potential earthquakes in the region.

The debate over the Liddell site is already contentious, with local opposition highlighting environmental concerns and the potential loss of jobs tied to alternative energy projects. Some in the Hunter Valley prefer plans for large-scale battery and solar manufacturing at Liddell, while others support the nuclear proposal for its potential to deliver stable, zero-emissions power.

Given the recent earthquake, these concerns are more relevant than ever. It underscores the importance of thorough geological studies and community consultation before moving forward with any nuclear infrastructure in the region

Community Reactions

The earthquake has sparked varied responses across social media, ranging from concern to humor. One user in Gunnedah shared, “Dogs were barking… scared the crap out of them,” while another joked about being in the middle of a field near Bengalla Mine when the tremor hit.

Locals in areas like Maitland, Lake Macquarie, and the Central Coast also reported feeling the earthquake, while others noted cracks in walls or swaying furniture. Anna Edwards, a resident near the epicentre, shared images of cracks in her home, noting it was the first time she had felt such a significant tremor.

Conclusion

While the quake has caused a stir across New South Wales, the lack of serious damage or injuries is a relief to residents. The event serves as a reminder of the seismic activity present even in typically stable regions like the Hunter Valley.

Further updates from Geoscience Australia and local authorities are expected as assessments continue throughout the day.