Effects published in the Bulletin of the Seismological Society of America recommend that some places along the fault, namely around the cities of Hokitika and Greymouth, would possibly delight in severe tremors due to alpine fault earthquakes more than that was thought.
The most productive paleo-asian evidence to date suggests that the southern and central sections of the Alpine fault, at the border separating the tectonic plates of Australia and the Pacific, are broken into very giant earthquakes of magnitude 7. 7 or more, the last of these earthquakes occurred in 1717.
However, after digging a ditch along the fault at the Staples site near the Toaroha River, Robert Langridge of GNS Science and his colleagues found evidence of a more recent earthquake along the northeastern end of the central component of the fault. earthquake between 1813 and 1848.
“One of the really demanding situations of the Alpine fault, because it is very covered in shrubs, is locating sites that have been cleared and can therefore be studied,” Langridge said. “Once we started running there [on the Staples site], the story literally grew largely because of the richness of biological matter in the trenches.
The 4 recent maximum earthquakes discovered through researchers in the diversity of the site from 1084 to 1848, the occasions were shown through knowledge collected from other trench sites and geological deposits called turbides, which are sediments shaken in a mass of water through seismic activity, in lakes. along the central component of the alpine fault.
The recent maximum earthquake may simply constitute a “component segment” rupture of the only central component of the alpine fault, a rupture of the northern segment of the fault that lasted southwest in the central segment, or even caused a rupture along the Marlborough closure. Falla. System. Langridge and his colleagues stated that there was still not enough evidence for one of those scenarios on the others.
However, the effects recommend that seismic activity in alpine failure is more complex than is suspected, that is, along its northern component, where the boundary of the board conforms to the fault zone.
“One of the effects of this study is that a shorter period of recurrence of strong tremors is expected at the end of the failure section,” Langridge said. “Due to earthquake recurrence times, it is clear that it is a long time to see the effects of such flawed behavior. “
“That’s why paleosismology is an essential tool for understanding failures,” he added, “because in a different way we would only have a brief look at the past. “
Alpine failure is rare compared to the San Andrés fault in California, as it is another fast-impact slip failure near a board boundary. Langridge said researchers in California and New Zealand have a long history of clinical collaboration on earthquakes and are informed from each about active fault resolution and fault segmentation for seismic hazard models.