Topics for Discussion with the Earthquake Demonstration

• Hypothesis 1: Earthquakes are periodic (in other words, all of the same slip, and all separated by the same amount of time). There is some evidence for this, particularly among very small earthquakes on creeping faults.
• Hypothesis 2: Earthquakes are 'time-predictable' (this means that the larger the slip in the last earthquake, the longer the wait until the next one.) This idea was formulated in the 1980's by Shimazaki and Nakata in Japan, and has been widely used.
• Hypothesis 3: Earthquakes occur randomly in time, with randomly varying size. (This 'Poisson' hypothesis is also widely used, particularly when little information about a fault and its past earthquakes is available).

The lecture notes sample (Microsoft Word 23kB Mar30 05) is a Word file that provides supplementary material to accompany the class discussion or lecture on earthquakes. It relates the elastic rebound model to the accumulation and release of strain energy in the earthquake model.