Earthquakes

A fault is..
a fracture in the earth where movement has occurred
An earthquakes epicenter is…
the epicenter is the location on the surface directly above the focus
When an earthquake occurs, energy radiates in all directions from its source, which is called the…
focus. the point within earth where the earthquake starts is called the focus
Earthquakes are usually associated with..
earthquakes are usually associated with large fractures in earths crust and mantle faults
What causes earthquakes?
earthquakes occur due to the release of built up energy
Most earthquakes are produced by the rapid release of elastic energy stored in rock that has been subjected to great forces..
went the strength of the rock is exceeded, it suddenly breaks causing the vibrations of an earthquake
Most earthquakes are produced by the rapid release of which kind of energy stored in rock subjected to great forces?
elastic energy stored in rocks
During an earthquake, ground surface…
can move in any direction
The adjustments of materials that follow a major earthquake often generate smaller earthquakes are called …
aftershocks
Major earthquakes are sometimes preceded by smaller earthquakes called…
foreshocks
The slow continuous movement that occurs along some fault zones is referred to as…
creep
The san francisco earthquake of 1906 occured along what fault?
san andreas fault
Which seismic waves travel most rapidly?
p waves travel more rapidly
What is true about p waves?
p waves are pull puch waves the push (compress) and pull (expand)rocks in the direction the waves travel. p waves are also known as compression waves
Overall which seismic waves are most destructive?
the surface waves are the most destructive, because surface waves move in and up-down , side to side motion. the side-to side motion is especially damaging to the foundation of buildings
What is the minimum number of seismic waves or amount of energy released at the source of the earthquakes epicenter?
three
An earthquakes magnitude is a measure of the size of the seismic waves or the amount of energy released at the source of the earthquake
10 times greater
what instrument records earthquake waves
seismographs
How much of an increase in wave amplitude is seen from an earthquake measuring 5.4 on the richter scale compared to one measuring 4.4?
10 times greater
A succession of ocean waves set in motion by a submarine earthquake is a
tsunami
Violent shaking from an earthquake can cause soil and rock on slopes to fail cause a _____ . . . . .
Landslide
Why do earthquakes often cause damaging fires ?
The fires started when gas and electrical lines were cut. Many city’s water lines had also been broken by the quake, which meant that the fires couldn’t be stopped.
Long-range earthquake forecasts are based on the idea that earthquakes are ______.
Repetitive or cyclical
What layers of earth make up the lithosphere ?
Crust and uppermost mantle
Through which Earth layer are S waves NOT transmitted ?
Outer core, because it is liquid
Earth’s core is made of an ally of _____.
Iron-nickel alloy
Wegener’s continental drift hypothesis stated that all the continents once joined together to form _____.
A single supercontinental
The supercontinent in the continental drift hypothesis was called _______.
Pangaea
In the plate tectonics theory, the lithosphere is divided by _____.
A tectonic plate consists of _____.
Crust and uppermost mantle
A divergent boundary at two oceanic plates can result in a ______.
Rift Valley
What type of boundary occurs where two plates move together, causing one plate to descend into the mantle beneath the other plate ?
Convergent boundaries
Give an example of a transform fault boundary ____.
San Andreas Fault
New Ocean crust is formed at ______.
Divergent boundaries
What occurs when divergence occurs between two oceanic plates ?
This process results in upwelling of material from the mantle to create new seafloor.
The Himalayas in South Asia are an example of what type of plate boundary ?
Continental-continental ( convergent boundary )
Volcanic island arcs are associated with type of plate boundary ?
Oceanic-oceanic ( convergent boundaries )