E3
Lesson Summary
Vocabulary Link
- hypocenter
- epicenter
- shallow-focus
- intermediate-focus
- deep-focus
- triangulation
- intensity
- quantitative
- qualitative
- logarithmic scale
- magnitude
- amplitude
- The hypocenter is the point of origin of an earthquake. The epicenter is the point on the Earth’s surface directly above the hypocenter.
- Earthquakes can be categorized by depth. Shallow-focus earthquakes occur at depths less than 70 kilometers (43 miles), intermediate-focus earthquakes occur between 70 and 300 kilometers (43 and 186 miles) depth, and deep-focus earthquakes occur at depths greater than 300 kilometers (186 miles)
- Signals from three separate seismic stations are needed to locate an earthquake epicenter.
- The Mercalli scale measures strength of earthquakes based on intensity.
- The Richter scale is a quantitative scale based on magnitude. It measures the amplitude of an earthquake’s largest recorded seismic wave.