earthquakes and volcanoes Flashcards
ring of fire
a region around much of the rim of the Pacific Ocean where many volcanic eruptions and earthquakes occur.
strike-slip fault
a fault in which rock strata are displaced mainly in a horizontal direction, parallel to the line of the fault.
normal fault
a dip-slip fault in which the block above the fault has moved downward relative to the block below
reverse fault
a geological fault in which the hanging wall appears to have been pushed up along the footwall.
p-waves
a seismic wave that causes particles of rock to move in a back-and-forth direction
s-waves
a seismic wave that causes particles of rock to move in a side-to-side direction
epicenter
the point on earths surface directly above an earthquakes starting point, on focus
focus
the point along a fault at which the first motion of an earthquake occurs
Richter magnitude scale
assigns a number to quantify the amount of seismic energy released by an earthquake
explosive volcano
a volcanic eruption of the most violent type.
nonexplosive volcano
most common type of volcanic eruptions
Krakatoa
In August 1883, the eruption of the main island of Krakatoa killed more than 36,000 people,
Yellowstone supervolcano
Yellowstone has had at least three such eruptions: The three eruptions, 2.1 million years ago, 1.2 million years ago and 640,000 years ago, were about 6,000, 700 and 2,500 times larger than the May 18, 1980 eruption of Mt. St.
San Andreas fault
a continental transform fault that extends roughly 1,200 kilometers through California
Mid-oceanic ridge
a continuous range of undersea volcanic mountains that encircles the globe almost entirely underwater
