oJapan is dangerous/susceptible to earthquakes because of “pacific plate” and Philippine plate
oEpicenter was about 80km offshore
oTsunami that was propagated – wave height increased dramatically as it reaches the shore.
oMap showed Japan shore areas moved 25m – whole of Japan moved east WHY?
2 plates were locked together & formed a lot of stress, after earthquake all the pressure
accumulated was released.
•Reoccurrence interval for SUPER earthquake 1000 years (build up 100 years of stress in
the plates) – Japan goes east and the pacific plate under goes west.
Normally plates only move 2.5cm a year
Tilting up of the ocean floor towards Japan caused the huge tsunami.
Geologic Time and Stratigraphy
•Stratigraphy – arranging rocks in a logical sequence according to their age
oGreek word “Strata” - layer
•How we measure time.
The Earth is 4.56 billion (4, 560 000 000) years old – how did we find this out?
Early Ideas on Stratigraphy (the study of rock layers as in a book)
•Greek found fossils were now on top of the mountain due to uplifting
•Alaskan cliff that has been uplifted – can see layers (stratas), accumulation of successive layers, each layer will
have a distinctive fossil type.
oCan use fossil and rocks from one location to correlate with another area (to find out the ancient
environments was like – paleogeography, what the world looked like in the past)
•Pic: Eastern Canada – folded rocks - Deformed when pangea was being formed (africa collided with eastern
•Strict biblical interpretations of earth’s history (rocks and landscapes result from Noah’s Flood)
oMore than one flood recognized (new life created each time so each layer contains different life forms)
oDiluvium – means “of a flood” – rocks were “diluvium”, associated with flood , they were deposited by
•Archbisshop Ussher (1581-1656)
oDeclared in 1625 that “earth formed at 9am on October 26th, 4004 BC” – based on counting generations
in the Bible
oEarth according to him was 6000 years old – fairly young Earth.
•Georgius Agricola (1494-1555)
oMining came along, people started digging hole and saw layers (strata) – asked whether each layers were
deposited at different times or in one time?
oFather of mining geology – book “De Re Metallica” 1556, after death
oRecognizes that fossils are remains of marine organisms in 1531
oNicolas Steno (1631-86) – “mountains can be raised and lowered, land can be conveyed from one place