Lecture 8 Japan earthquake: o Japan is dangeroussusceptible to earthquakes because of pacific plate and Philippine plate o Epicenter was about 80km offshore o Tsunami that was propagated wave height increased dramatically as it reaches the shore. o Map 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 o Greek 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.