Govind Tekale
A 4.6 magnitude earthquake centered near Broke in NSW’s Hunter Valley jolted residents awake early Wednesday morning, with vibrations felt across a wide area including Sydney’s high-rise buildings.
The quake struck at 2:55 AM on April 23, 2025, approximately 25 kilometers southwest of Singleton at a depth of 10 kilometers, data from Geoscience Australia shows. By 7:45 AM, more than 3,500 people had reported feeling the earthquake through Geoscience Australia’s website.
People reported feeling the tremors as far north as Tamworth, south to Canberra and Wollongong, and west to the Blue Mountains.
Phil Cummins, a senior seismologist at Geoscience Australia, described the event as “pretty large for Australia” and “significant.” He noted that the shaking had been widely felt, with many reports indicating moderate to strong tremors.
Amplified Effect in Tall Buildings
The earthquake’s effects were particularly noticeable in Sydney’s high-rise buildings, with more than 50 residents in Wentworth Point and numerous others in Mascot reporting the tremors.
One Wentworth Point resident told Today that he felt really strong movements throughout his entire apartment. He described feeling confused about what was happening, finding the experience both amazing and frightening.
Dr. Ehsan Noroozinejad Farsangi from Western Sydney University explained why high-rises experience stronger earthquake effects. He stated that people on upper floors feel earthquakes more intensely because tall buildings are designed like giant springs that sway and amplify ground motions at higher elevations.
“That extra wobble is a feature, not a flaw: the structure is flexing to dissipate energy, so it’s no more likely to collapse than a shorter, stiffer building. The real problem is psychological; our brains equate movement with danger,” Dr. Farsangi explained.
Firsthand Experiences
People near the epicenter and in surrounding regions shared varied experiences of the earthquake. Carma Matthews, staying at a caravan park in Broke, said the tremor was brief but powerful enough to shake their entire caravan, initially making her companion Barry McDonald think someone was physically rocking it.
About 120 kilometers east in Tea Gardens, nursing home resident Jenny Bennett felt her bed rock and wardrobe doors rattle, accompanied by what she described as a loud rumbling sound from outside.
Newcastle resident Alan Berry was up getting water when he heard what sounded like something hitting the side of his house, followed by rattling from his outdoor fence and gate while his bed moved.
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Part of Ongoing Seismic Activity
The earthquake is the latest in a series of seismic events in the Hunter Valley region. Geoscience Australia has recorded 11 earthquakes with a magnitude of 3 or greater in the area over the past 12 months.
Previous significant tremors include a magnitude 4.7 quake near Muswellbrook on August 23 last year, followed by a 4.5 magnitude event just one day later. Additional earthquakes measuring 4.5 and 4.1 occurred in the same area on September 7 and November 12 respectively.
Cummins explained that Australian earthquakes result from tectonic stress buildup. These stresses come from forces at tectonic plate boundaries thousands of kilometers away, eventually exceeding the strength of faults in the Earth’s crust and causing earthquakes.
Historical Context
The Hunter region has experienced notable earthquakes historically, including the Ellalong earthquake (magnitude 5.4) in 1994 and the Newcastle earthquake (magnitude 5.6) in 1989.
Wednesday’s earthquake epicenter was located near the Mount Thorley Warkworth open-cut coal mine. However, earthquake geologist Dee Ninis from Monash University indicated that the quake’s depth suggests it was not mining-related.
Limited Damage Reported
Despite the widespread impact, no injuries were reported. The NSW State Emergency Service received numerous calls from concerned residents but only responded to one incident – a burst water pipe at a property in Rutherford near Maitland shortly after the earthquake.
Hunter MP Dan Repacholi, who was awakened by the tremor, commented on social media that most of the Hunter region likely felt the shake. He mentioned that his team was ready to assist with any damage.
Aftershocks Anticipated
Geoscience Australia has advised that aftershocks are expected to follow. According to Cummins, these aftershocks will likely be smaller than the main quake but may still be felt by residents. He indicated that aftershock activity could continue for several days or potentially more than a week.
The Joint Australian Tsunami Warning Centre has confirmed that the earthquake posed no tsunami threat to Australian territories.
