During an earthquake and over time, the fractured rocks come down in landslides and rivers carry them to the sea. Republish our articles for free, online or in print, under Creative Commons licence. In the new study, the interval between earthquakes ranged from 160 to 350 years and the probability of an earthquake occurring in the following 50 years was estimated at 29 per cent. Average slip rates in the fault's central region are about 30mm a year, very fast by global standards. So while earthquakes are an important part of oral tradition, no stories have been passed down about South Island Earthquakes. This will help us to develop better computer models of earthquake rupture.
By the early 21st century, information about the risks associated with the Alpine Fault is common-place. Over the last thousand years, there have been four major ruptures along the Alpine Fault causing earthquakes of about magnitude 8. The Pacific Plate and Indo-Australian Plate boundary forms the in the off the southwestern corner of the South Island and comes onshore as the Alpine Fault just north of Milford Sound. Quite early on, European settlers were faced with the reality of earthquakes in their new home. Exercise Te Ripahapa—loosely translated as Boundary Fault—would be the most comprehensively scripted Civil Defence exercise ever undertaken in New Zealand. The scientists estimate that recent events were between magnitudes of 7.
It was the first time a collective South Island-wide response plan had been attempted. Warrant Officer Simon Cole, representing the Army, has requested a P3 Orion for aerial reconnaissance. The fault was officially named the Alpine Fault in 1942 as an extension of a previously mapped structure. Old geology acknowledged an alpine uplift, but the prevailing explanation for coastal mountains was an offshore trough, the geosyncline, that sagged under an increasing burden of sediment, put pressure on the mantle, and the mantle—by the principle of isostasy—responded to its load and rebounded like a trampoline. Welcome to the Alpine Fault earthquake.
The 100-metre and 150-metre probes of stage one were comparatively shallow. Photo: Supplied The simulation showed that a magnitude 8 quake could cause shaking across the whole South Island. But early results from the new approach have proven encouraging, and could offer an exciting new way to address uncertainties. However, most of the valleys in the region where we drilled have a few warm springs that hint at this deeper source of hot water. If he wants to commandeer a helicopter from—say—the media, he can do it.
Choi, Live Science Contributor on. Partway through the three-year study, Yetton met Andrew Wells, just then pioneering the new field of dendrology. The hot, high-pressure water beneath the valleys is mostly invisible at the surface, because it mixes with shallow, cold groundwater that flows to a depth of about 50 metres at our drill site. Other faults around the world that we know are similar to the Alpine Fault may also have extreme conditions that have never been investigated. Reilly now has powers of control and compulsion.
The flow needs to be fast enough so that the heat is not lost along the way, just as a water pipe in your home moves heat from a hot water cylinder to your bath before having time to cool. Yet South Island seismometers recorded few shakes on the fault, so maybe it was aseismic, maybe it simply crept, the compression of the plates taken up by elastic strain across the Alps, or absorbed in ductile zones. There is a 28 per cent chance it will happen in the next 50 years, which is high by global standards. This includes and the , which increases in towards the fault. The co-ordination between the Canterbury team and the Fire Service, police, St John Ambulance and Army also worked well.
It is the first time this has ever been done on a major fault that is due to fail in coming decades. New Zealand was within the last five minutes of the next chime. In fact, the intervals between the 24 successive earthquakes measured at Lake McKerrow varied between 140 years and 510 years. The rivers were excavating across a major unconformity. Our findings, , describe these surprising underground conditions. Also near the surface the fault can have multiple rupture zones. A powerful tsunami on New Zealand's west coast will devastate both the South and North Islands of New Zealand, and damage will occur as far north as New Plymouth and as far south as Stuart Island.
An international team that drilled almost a kilometre deep 0. Visible from space, it extends for about 650km from south of Fiordland along the spine of the Southern Alps and into Marlborough. This process has operated for millions of years, with the height of the mountains staying about the same. There was little specialist attention to tectonics, which was simply stratigraphy on the move. Prehistoric dates of the most recent Alpine fault earthquakes, New Zealand.
Research over the past four decades has added considerably to the understanding of its rupture history and the likely impacts from its next big earthquake, which could change the face of the country and lives within it forever. The story is told instead by trees, sediments, and the landscape of the South Island's West Coast. He said in his area the advice remained the same - to ensure they were prepared. Most damage in a major quake is done and dusted within minutes. The rapid uplift also means that faulted rock from deep down has been brought to the surface, and can be studied by scientists. Yetton backed up these dates with evidence for rupture length, using trench data and forest disturbance patterns. The patterns are evident from Jackson Bay up the West Coast to Lake Kaniere near Hokitika compiled graphic on this and following pages ; a continuous line of shattered land, physical evidence of a world-ranked master fault.
The maths was simple—an average of one Alpine Fault earthquake every 330 years, the last one in 1717. Aftershocks will continue for years, including a magnitude 7. How does it get so hot There are two processes we think explain the extreme underground conditions at our drill site. He covers all things human origins and astronomy as well as physics, animals and general science topics. He turns with a bright smile.