New Zealand, is located on multiple faults, which means that its land mass is continuously changing and shifting, ranging from a few millimeters to inches. Some of these changes occur over years, and others happen within a few minutes. Because of the variability, with earthquakes, faulting, volcanic activity, and weather, landslide activity is frequent when compared to other countries. All of these things can play a factor when thinking of landslides, though not the causes themselves, for example, if a slope is formed on weak layers of volcanic ash, then it is far less stable and is likely to produce a mass movement.
Many different types of landslides can affect New Zealand, including, alpine slides, low mountain landslides, layered rock landslides, rotational landslides, creeping earth flows, regolith landslides, and submarine landslides. While these all seem daunting, making life on this tiny country unfeasible, the mortality rate caused by landslides is lower than most countries for a few different reasons. The first is relatively obvious; there are not a lot of people living in high-risk areas. The second reason is preparation, through technological advances seismic sensors are scattered throughout the islands and can identify when the chances of a landslide are increased and send alerts to the at-risk communities. Probably the most critical factor in New Zealand's low mortality rate with an unpredictable landscape is working proactively, instead of reacting to a disaster.
Sources:
https://www.gns.cri.nz/Home/Our-Science/Natural-Hazards/Landslides
http://www.learnz.org.nz/geohazards152/landslides-in-new-zealand
Greta research- They have recently added a database so you can see their risk maps and all the information gathered to date...pretty cool [see link below]
ReplyDeletehttps://link.springer.com/article/10.1007/s10346-017-0843-6