Flashcards in Lesson 4 Deck (32):
is the shaking of the surface of the Earth, resulting from the sudden release of energy in the Earth's crust that creates seismic waves.
is a fault that is likely to become the source of another earthquake sometime in the future.
active fault line
Geologists commonly consider faults to be active if there has been movement observed or evidence of seismic activity during the last _____years
It is the total energy released at the earthquake’s point of origin which is below the earth's surface.
Not felt. Detected only by sensitive seismographs under favorable conditions
Hardly perceptive. Detected by seismographs
"Very feeble". Felt only near the epicenter
"Feeble" generally felt but dont usually cause any damage
"Moderate" earthquake --May-- cause local damages
"Strong" earthquake. ---Usually--- cause local damages
"Major"earthquake. Causes considerable widespread damages; maybe accompanied by surface rupture and tsunami
"Great" earthquake. Potentially devastating
Rare earthquake . only 5 recorded since 1900
Is the perceived strength of an earthquake based on the relative effect to people and structures on the earth’s surface.
Scarcely perceptible-perceptible to people under favorable circumstances
Slightly felt- Felt by few individuals at rest indoors
Weak-Felt by many people indoors especially in upper floors of buildings
Moderately Strong -Felt generally by people indoors and by some people outdoors
Strong -Generally felt by most people indoors and outdoors
Very Strong- Many people are frightened
Destructive -Most people are frightened and run outdoors
Very Destructive -People are panicking
Devastating -People are forcibly thrown to the ground
Completely Devastating -practically all man made structures are destroyed
Is caused by the passage of seismic waves beneath structures.
Is the displacement of the ground due to the violent shaking of the surface.
occurs when one side of the ground goes up or down or both.
is a lateral movement from side to side.
Takes place when there is an increase in water pressure in saturated soils because of ground shaking.
is a form of mass wasting that includes a wide range of ground movements, such as rockfalls, deep failure of slopes, and shallow debris flows.
The lowering of the land surface occurs for many reasons, such as the extraction of ground water, mining, and earthquake.