Earth Science Slow Earthquake ?

Discussion in 'Earth Science' started by helenheaven, Nov 16, 2004.

  1. helenheaven

    helenheaven Premium Member

    Wow, apart from glaciers moving, I didn't think such a thing would happen

    A piece of land near Gisborne is on the move - literally.

    Scientists have detected what they are calling a "slow earthquake".

    The land began moving eastward on October 31 at nearly two millimetres a day.

    It is still moving but scientists expect the rate to start to slow any day now.

    The motion has almost certainly been caused by movement on the boundary between two tectonic plates about 20km under the seafloor in Poverty Bay.

    Two millimetres a day is ten times faster than normal motion of land on the North Island's East Coast due to tectonic forces.

    It is the second time the unusual phenomenon has been observed in the region.

    In 2002 an area of Poverty Bay moved eastward for a week then stopped.

    In both cases, the movement was detected on a continuously recording GPS instrument run by the GeoNet project, which is funded mainly by the Earthquake Commission.

    Scientists first detected slow earthquakes overseas about eight years ago.

    Since then they have been recorded in Canada, Mexico, Japan, and Costa Rica, as well as in New Zealand.
  2. Zsandmann

    Zsandmann Premium Member

    Hmmmm. Ok I understand a tectonic movement would create an earthquake, but I dont like the term 'slow'. The actual land movement sounds like a slump. A slow moving laterally continous 'chunk' of land that becomes detatched and moves via gravity.
  3. junior_smith

    junior_smith Premium Member

    ian't 2 mm a day 'fast'in terms of tectonic plates and such? i mean everest grows about 1mm a year, and you really only hear of a big movement in tectonic plates everytime there is an earth quake
  4. Zsandmann

    Zsandmann Premium Member

    2mm is 'fast' tectonically yes, wat they mean is that it is creating a prolonged seismic output, or 'slow' earthquake. Usually earthquakes only last seconds.