Earthquakes and Volcanoes Flashcards
A region around much of the rim of the Pacific Ocean where many volcanic eruptions and earthquakes occur.
ring of fire
Vertical fractures where the blocks have mostly moved horizontally.
Strike-slip fault
A dip-slip fault in which the block above the fault has moved downward relative to the block below.
Normal fault
The block above the fault moves up relative to the block below the fault.
Reverse fault
The first waves to arrive at a seismograph.
P-waves
The second waves to hit the seismographs.
S-waves
The point on the earth’s surface vertically above the focus of an earthquake.
epicenter
A point at which rays of light, heat, or other radiation meet after being refracted or reflected.
focus
Quantitative measure of an earthquake’s magnitude.
Richter magnitude scale
If a lot of gas is trapped within magma, pressure will build and build until eventually the magma erupts explosively out of the volcano.
explosive volcano
Generally occur when magma is thin and flows easily.
nonexplosive volcano
A volcanic island in Indonesia, in the Sunda Strait between Java and Sumatra.
Krakatoa
A volcanic center that has had an eruption of magnitude 8 on the Volcano Explosivity Index.
Yellowstone supervolcano
The transform boundary between two major plates of the Earth’s crust: the Northern Pacific to the south and west and the North American to the north and east.
San Andreas fault
A continuous range of underwater volcanoes that wraps around the globe like seams on a baseball, stretching nearly 65,000 kilometers.
Mid-oceanic ridge
