Part 3

Seismometers and Seismograms A seismogram is the record produced by a seismometer (or seismograph).

Zhang Heng made his earthquake recorder, the first ever known, in 132 AD. It was designed to work out the direction in which waves from earthquakes were traveling.

Earthquake Magnitude and Intensity Magnitude: energy released. Richter Scale: based on the size of largest seismic waves. Measures magnitude. –Increase of 1 on scale –10-fold increase in seismic wave size. –32-fold increase in energy.

–Modified Mercalli scale: amount of damage done to structures. –Measures intensity = damage. –This scale uses Roman numerals I to XII –Higher numeral = more damage

Some Earthquake Hazards The damage related to the strength or quality of the structures:. Severe damage: unreinforced buildings made of stone, concrete, or other brittle materials. Little Damage: wooden structures, steel-frame buildings.

End of Custom Shows This slide is intentionally blank.