Turbulent waves moving through Earth's core offer fresh insights for future planetary exploration

ANU geophysicist and study co-author, Professor Hrvoje Tkalčić, says the study findings could be useful in the exploration of icy planets and moons. Photo: Tracey Nearmy/ANU 

New research from The Australian National University (ANU) suggests that energy signals from powerful winter storms in the North Atlantic, which travel through Earth’s core, could improve our understanding of the solar system.

ANU seismologists detected PKP waves—core waves produced by cyclones in the North Atlantic—using two 50-by-50-kilometre spiral sensor arrays located in remote areas of Australia. These waves pass through Earth's center and arrive in Australia during the summer.

The study pinpointed Greenland and Newfoundland as the main sources of these seismic signals caused by ocean wave activity.

Abhay Pandey, ANU PhD student and co-author of the study, highlighted the importance of this detection method. He explained that the specially designed technology used in remote Australia is vital for studying core waves and could be instrumental in exploring other planets.

“This technique can help identify planets with cores—even those lacking plate tectonics, volcanic activity, or seismic events—offering valuable insights for future planetary missions,” he said.

Study co-author and ANU seismologist, Professor Hrvoje Tkalčić, explained that if a seismometer array could be placed on the surface of a small, quake-free planet, the technique from their research might be useful for examining its interior by detecting signals from atmospheric or hidden ocean activity—similar to those observed in their study.

He noted that the team used a specially designed setup consisting of two spiral-arm seismometer arrays, carefully installed in remote regions of Queensland and Western Australia. These instruments captured and analyzed waveforms to detect microseismic signals with long wave periods.

The findings demonstrate how storm-driven ocean waves in the North Atlantic can transmit energy through Earth’s core, offering valuable data for understanding the planet’s internal structure.

This recorded “microseismic noise” results from interactions between ocean waves and Earth’s solid surface, generating seismic waves.

Using advanced array-seismology methods, the ANU team pinpointed the signal source in the North Atlantic, particularly near southern Greenland and the ocean’s deeper areas.

“We compiled data across several days to locate where the signals were strongest, shedding light on their origins and how they travel through the Earth,” added Mr. Pandey.

“These signals are extremely faint—often too weak to be detected by a single sensor—so specialized instruments are required to capture them,” the researchers explained.

“Although challenging to observe, Australia’s remote and geologically quiet locations, along with its unique geographic position, make it an ideal setting for detecting such signals.”

The transmission of microseismic waves is affected by numerous factors, including cyclone activity throughout the year, ocean depth, seafloor topography, distance from the wave source, the frequency range used in observation, and the sensor types involved.

“Our study focused on a seismic period band of four to six seconds, which is key to detecting these specific signals,” Mr. Pandey said.

While the North Atlantic is seismically active, the small magnitude and nature of its quakes make it difficult to use traditional seismic data to study Earth’s deep interior.

“Our work leverages microseismic activity as an alternative means to investigate Earth’s structure beneath Australia—our island continent surrounded by sea,” said Professor

Tkalčić.

“These signals are intricate and change depending on the source location and the path to the receiver. Capturing them effectively requires advanced techniques and modern infrastructure, such as Australia’s national ocean bottom seismometer network.”