New Zealand researchers have discovered an unusual factor that could affect the magnitude of the next devastating earthquake in the Hikurangi subduction area, namely, the fossils of tiny marine organisms that lived tens of millions of years ago.
A thorough study of the subduction zone is necessary to accurately predict earthquakes, but its location in the sea and depth make it difficult to do so. In a new study led by Dr. Caroline Bulton of Wellington University, scientists examined a rock crumbling of Hungaroa, which is located on the outskirts of the Hikurangi subduction area.
They focused on limestone, argillite and alevololite layers on a cliff 35 kilometres south-east of Martinborough, which were used as an indicator of what was happening in the marine subduction zone, which appeared between 35 and 65 million years ago.
Researchers have found large amounts of calcite in these species, a common carbonate mineral that, in this case, remains from ancient single-cell marine organisms, mainly foraminifer, such as plankton, and scientists have observed that the deposition of calcite from long-dead tiny marine organisms can affect the mechanical interaction of two huge tectonic plates.
If the calcite is dissolved in sufficient quantities, it will weaken the fracture. As a result, two tectonic plates can slide softly without causing visible earthquakes on the surface. However, if the rock does not dissolve, the fracture line will block and the stored energy will eventually be released in the form of a severe earthquake. The probability is that it will occur over the next 50 years in the Hikurangi subduction area in New Zealand is 26%.
The Hikurangi subduction zone is the largest fracture on New Zealand ' s plate border off the east coast of the northern island, where two stoves come together, where the Pacific plate is sunk under the Australian stove, and there may be major earthquakes in the region, with the potential for an event of more than eight points in the history of the observations.