Unimore joins international team that uncovers link between climate change and tsunami risk
Over 250 million people—around 5% of the global population—live along the coasts of the South China Sea. Understanding the geological factors that influence tsunami risk in this region is therefore crucial for the protection of coastal populations and infrastructure, both on land and underwater.
Tsunamis are primarily triggered by earthquakes and submarine landslides occurring along continental margins. Identifying the geological factors that affect their frequency and distribution is essential for developing effective risk mitigation strategies.
A major step forward in this regard comes from a new study published in the prestigious journal Nature Communications, conducted by an international team of scientists from China, Europe and Canada, including Professor Vittorio Maselli from the Department of Chemical and Geological Sciences at the University of Modena and Reggio Emilia.
The study, coordinated by Qiliang Sun and Xingxing Wang of the China University of Geosciences in Wuhan and funded by the National Natural Science Foundation of China, revealed that sediments rich in biogenic silica—derived from the accumulation of diatoms and radiolarians (unicellular marine microorganisms)—promote the formation of mechanically weak layers that can trigger submarine landslides with the potential to generate tsunamis.
By integrating geophysical data with geotechnical parameters obtained from sediment cores collected through the Ocean Drilling Program, the team discovered that these “weak layers,” are deposited cyclically approximately every 100,000 years during glacial periods—phases of global cooling driven by Earth’s orbital variations. During these times, sea levels dropped by up to 120 metres compared with today, the Asian monsoon intensified, and the supply of sediments and nutrients from the continents to the ocean increased. These conditions stimulated high oceanic primary productivity, leading to a substantial accumulation of siliceous material on the seafloor. The repetition of this process contributed to the formation of the weak layers, making the sediments along the continental slope more susceptible to instability when subjected to stress, such as an earthquake.
“This study provides clear evidence of a link between climatic oscillations and factors that can increase the risk of submarine landslides,” explains Professor Vittorio Maselli. “We have demonstrated this for the South China Sea, but it suggests that other continental margins with similar oceanographic and climatic conditions may show a comparable cyclicity in their sedimentary records.”
Categorie: International - english, Notizie_eng
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