Earthquakes Characteristics and Spatial Extent IB Geography Focus on: Their spatial extent, predictability, frequency, magnitude, duration, speed of onset and effects.

Global Tectonic Plate Map

Describe the global distribution of earthquakes that have occurred in the last 7 days? [You could get an exam question like this based upon a given map!]

Mag 5+ since 1980-1990 Look at the global distribution of earthquakes with a magnitude 5 or greater that have occurred between 1980-90. Is there any difference between the observed distribution and the distribution of earthquakes that have occurred in the last 7 days?

Task 2 The following are elements of an earthquake hazard: Time of earthquake Date of earthquake Exact location of epicentre Fault upon which the quake occurs The magnitude of the earthquake The economic impact of the earthquake The death toll of the earthquake For each of the elements explain how predictable it is.

Task 3 Read the BBC article and highlight the following in different colours: Locations Dates Numbers/Values Any prediction Any basis upon which a prediction is made Any issues with earthquake prediction

Something to think about ... earthquake frequency Are earthquakes becoming more common? Are there any patterns in the two illustration above?

Average Frequency Magnitude Average Annually 8 and higher 1 ¹ 7 - 7.9 17 ² 6 - 6.9 134 ² 5 - 5.9 1319 ² 4 - 4.9 13,000 (estimated) 3 - 3.9 130,000 (estimated) 2 - 2.9 1,300,000 (estimated) ¹ Based on observations since 1900. ² Based on observations since 1990.

Essay Question Essay Question (10) Evaluate the statement: "There were more deaths from earthquakes in the last decade than the one before so earthquakes are becoming more common."

Magnitude Produce notes on the following three scales of magnitude used to measure earthquakes: Richter Scale, Moment Magnitude Scale and the Modified Mercalli Scale.

Alaska 1964 – 9.2

Asia 2004 9.3

Chile 1960 9.5

Power of resultant tsunami