### earthquake:

Big earthquake
* can take down buildings and cause death and injury.
* occur regularly with many occurring under the ocean or in sparsely populated areas.
+ Earthquake: Plate tectonics
  * There are large earthquakes and small earthquakes. Big earthquakes can take down buildings and cause death and injury. The study of earthquakes is called seismology. Seismology studies the frequency, type and size of earthquakes over a period of time.

Bigger earthquake
* have more and larger aftershocks.
* trigger more aftershocks with larger magnitudes.

Deep earthquake
* are the most common in the Pacific Northwest.
* occur in areas where oceanic crust is being actively subducted.

Intraplate earthquake
* have in general higher stress drop than interplate earthquakes.
* occur within the plates at places where the crust is fracturing internally.

### earthquake:

Large earthquake
* Most large earthquakes cause disasters
  - tsunamis
* Most large earthquakes occur in areas
  - on long fault zones around the margin of the Pacific Ocean
  - strike northern regions
* Some large earthquakes do trigger eruptions.
* are common along such strike-slip, or transform,boundaries
  - rare occurrences
  - relatively rare
* can form ponds and lakes due to sudden down-shifts in valley floors
  - occur nearly everywhere in Nevada
  - violent motions of the earth's surface
* rupture faults that are tens to thousands of kilometers long.

Magnitude earthquake
* Most magnitude earthquakes cause damage
  - widespread damage
* Most magnitude earthquakes destroy areas
  - neighbor areas

Massive earthquake
* Most massive earthquakes cause damage.
* Some massive earthquakes cause death.

Microseism
* interfere with the recording of primary, secondary, and long waves.
* is an earthquake

Powerful earthquake
* Most powerful earthquakes destroy structures.
* Some powerful earthquakes occur in rings.
* can shake firm ground violently for great distances
  - from great distances

Severe earthquake
* are a worldwide problem.
* occur and volcanoes occasionally erupt with much destruction.

Small earthquake
* Many small earthquakes occur in the area surrounding the magma as the rocks break.
* occur from time to time in Kansas.
* rupture small faults or small sections of large faults.

Strong earthquake
* are common at subduction zones
  - fairly rare, but there are light tremors from time to time
  - very rare phenomena
* cause landslides, great destruction, and loss of lives.
* occur in Iran with a frequency unheard of almost anywhere else on Earth.

Tectonic earthquake
* are much more powerful than the earthquakes caused by volcanic activity.
* occur due to the release of the stress caused by relative plate motion.

Volcanic earthquake
* Most volcanic earthquakes are small.
* are almost always due to the movement of magma
  - generally much smaller and less intense than tectonic ones
  - minor or at most moderate in magnitude
  - usually low in magnitude but can be felt because of their shallow depth

### earthquakes:

Major earthquake
* Most major earthquakes occur in areas.
* are earthquakes.
* can kill thousands of people.

### easily frightened away:

Female turtle
* Most female turtles dig pits
  - leave tracks
* Most female turtles maintain body temperature
* Most female turtles share instinct
  - nest instinct
* Most female turtles use feet
  - hind feet
* Some female turtles dig holes
  - emerge at nights
* Some female turtles leave oceans
  - water
* Some female turtles return to beaches
  - nest sites
  - same nest sites
* are easily frightened away
  - larger than males
* can store sperm for years.
* go ashore to lay eggs.
* lay their eggs in holes that they dig in the ground and leave.
* leave their aquatic environment and venture onto dry land to lay their eggs
* tend to move on shore to nest in large synchronized concentrations
  - onshore to nest in large synchronized concentrations