RSES seminar • July 29 1 pm • Hrvoje Tkalčić

Non Seismologist’s Guide to Seismology: From the Earth’s core to Mars and back


Hrvoje Tkalčić
Research School of Earth Sciences
Australian National University

July 29 • 1 pm (AEST)

In-person seminar at Jaeger 1 seminar room

Seminar will also be broadcasted on Zoom
( ID 606 666 0101, password: jaeger)


Seismology has come a long way in providing insights into Earth’s internal structure and dynamics. Among many forward and inverse geophysical techniques developed, full-waveform modelling, seismic tomography and receiver-based studies enabled detailed imaging of Earth’s subsurface. Apart from earthquake waves, analysing the Earth’s ambient noise in the last two decades revolutionized Earth’s interior studies. That enabled imaging of Earth structure in places where earthquakes or receivers do not exist.

At the same time, progress in imaging the Earth’s deepest shells has been impeded by the uneven global distribution of earthquakes and receivers and the fact that the ambient noise studies cannot reach deeper than the uppermost Earth’s shells. In seeking the ways forward, we started experimenting with similarity – comparing digital waveforms recorded at different locations many hours after the onset of large earthquakes. As in many science disciplines, initial work on this topic resulted in controversies and led to new realisations and discoveries that altogether contributed to the rise of a new concept – the correlation wavefield, a common theme throughout my talk.

“Detecting similarity between weak signals is more valuable than detecting them.”

Once this concept is fully understood through theoretical developments, it becomes a powerful way to study Earth’s deep structure, including its innermost shell – the inner core. I will provide a review of my group’s most important results and ambitions to date, with brief stops at the Earth’s centre and its various shells, the Southern Ocean bottom, Mars, the Outback and Antarctica. I hope to demonstrate that this new concept may play a central role in global and planetary seismology in the coming decades.

For seminar schedule, visit RSES Seminars Thursday 1pm | ANU Research School of Earth Sciences (sourced from researchseminars.org

For past recordings, visit

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RSES Seminar Committee
(Michael Anenburg, Sarah Jackson, Voon Hui Lai, Louis Moresi)