Haitian earthquake. Photo: Getty

GEOLOGY

Earthquakes themselves affect the movement of Earth’s tectonic plates, which in turn could impact on future earthquakes, according to new research from the University of Copenhagen. This new knowledge should be incorporated in computer models used to gauge earthquake risk, according to the researchers behind the study.

Like a gigantic puzzle, Earth’s tectonic plates divide the surface of our planet into larger and smaller pieces. These pieces are in constant motion due to the fluid-like part of Earth’s mantle, upon which they slowly sail. These movements regularly trigger earthquakes, some of which can devastate cities and cost thousands of lives. In 1999, the strongest European earthquake in recent years struck the town of İzmit, Turkey – taking the lives of 17,000 of its residents.

Among researchers and earthquake experts, it is well accepted that earthquakes are caused by a one-way mechanism: as plates move against one another, energy is slowly accrued along plate margins, and then suddenly released via earthquakes. This happens time and again over decades- or century-long intervals, in a constant stick-slip motion.

But in a new study, researchers from the Geology Section at the University of Copenhagen’s Department of Geosciences and Natural Resource Management demonstrate that the behaviour of tectonic plates can change following an earthquake.

Using extensive GPS data and analysis of the 1999 İzmit earthquake, the researchers have been able to conclude that the Anatolian continental plate that Turkey sits upon has changed direction since the earthquake. Data also show that this influenced the frequency of quakes around Turkey after 1999.

“It appears that the link between plate motion – earthquake occurrence is not a one-way street. Earthquakes themselves feed back, as they can cause plates to move differently afterwards,” explains the study’s lead author, postdoc Juan Martin De Blas […]

Map of the Earth’s largest tectonic plates. Photo: Getty

Continue reading: https://news.ku.dk/all_news/2022/03/groundbreaking-earthquake-discovery-risk-models-overlook-an-important-element/