Slow slip events generally happen next to areas where faults are locked and expected to rupture in major earthquakes. Even in the short time of a couple of decades that we’ve observed these types of slip, many cycles have occurred in several places – notably around the Pacific Rim. Compared to major earthquakes, which have repeat times of hundreds of years (or more), slow slip events are actually very frequent. Slow slip events repeat at intervals of a year to a few years. Using the same definition, many slow slip events would have had magnitudes above 7.0 if they slipped at earthquake speeds. Earthquake magnitude depends on the distance that rocks move and the area this movement occurs over. This means they need to be studied by GPS networks rather then seismometers.Īlthough their motion is slow, the amount of movement that occurs in a slow slip event is substantial. Slow slip events occur faster than average plate motion, but too slow to generate measurable seismic waves. These “slow slip events” last for weeks to months, compared to seconds to minutes for earthquakes. In the last two decades another class of stick-slip motion has been discovered worldwide. This slip also releases energy as the seismic waves that, in large magnitude earthquakes, create substantial damage. Earthquakes result from a “stick-slip” motion, where rocks “stick” along fault planes while stress accumulates until a “slip” occurs – a bit like pulling on a stuck door until it suddenly opens. These earthquakes, and their aftershocks, happen because although tectonic plates move at centimetres per year, this motion is seldom steady. You’re probably familiar with earthquakes as relatively short, sharp shocks that can shake the ground, topple buildings and tear rips in the Earth.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |