Magnitude 5.5 Earthquake Recorded in Remote APY Lands

A magnitude-5.5 earthquake was recorded at 3:56 AM on Sunday in Amata, a community located within the Anangu Pitjantjatjara Yankunytjatjara (APY) Lands near the South Australia and Northern Territory border. Geoscience Australia reported receiving approximately 30 accounts from individuals who felt the seismic event.

Event Summary

The earthquake, measuring magnitude 5.5, occurred at 3:56 AM on Sunday. Its epicenter was situated near Amata, South Australia, within the APY Lands, close to the border with the Northern Territory. Geoscience Australia confirmed the seismic event.

Reported Observations

Approximately 30 reports were received by Geoscience Australia from individuals who experienced the earthquake. Residents in areas including Yulara, Uluru, and Mutitjulu reported being woken by the event. Observers described experiencing light to moderate shaking. There were also reports of light fixtures swinging and items rattling on shelves.

Expert Commentary and Analysis

Jonathan Bathgate, a senior seismologist at Geoscience Australia, stated that the earthquake's magnitude was comparable to the 1989 Newcastle earthquake. The limited impact observed in the remote APY Lands was attributed to the epicenter's location away from densely populated centers.

The 1989 Newcastle earthquake, also a magnitude 5.5, resulted in fatalities, injuries, and an estimated $4 billion in damages, highlighting the reduced risk for remote epicenters.

Following the main quake, several aftershocks, ranging from 2.8 to 3.6 on the Richter scale, were recorded after 9 AM. These aftershocks were primarily felt near the epicenter, specifically in the Amata area. Bathgate noted that aftershock sequences typically decrease in frequency and magnitude over time, though the possibility of another larger earthquake within the sequence cannot be ruled out.

Regional Seismic History

The Amata area and the broader region have a documented history of seismic activity, capable of producing significant earthquakes. Notable past events include:

• 2012 Ernabella (Pukatja) Earthquake: A magnitude-5.4 earthquake was recorded at Ernabella (Pukatja). At the time, this was considered the largest inland earthquake in 15 years.
• 2016 Petermann Ranges Earthquake: A magnitude-6.1 earthquake occurred in the Petermann Ranges, which resulted in a 20-kilometer-long fault scarp.