GEOLOGY 201 QUIZ 4 EXAM QUESTIONS WITH
VERIFIED ANSWERS
Place of first rupture in an earthquake?
hypocenter or focus
The projection of focus to surface is?
epicenter
What is a surface wave?
seismic waves that travel along the earths surface
What are the types of body waves?
Non-directional; P & S waves; they are not confined to the earths surface, travel through earths
interior, both elastic
What is a P wave?
Primary wave. A body wave. generated by a sudden compression or extension of the ground at
the site of an earthquake, push or pull at a stretched spring
What is an S wave?
Secondary wave. generated by shearing or sliding motion at an earthquake site i.e. when rope is
shaken
What are the types of surface waves?
L & R waves
What is an L wave?
moves like a snake
What is an R wave?
up and down waves, comes from P waves, ripple effect
How is the size of an earthquake described?
its size and magnitude, Mw; it increases in value as amount of energy released during an
earthquake increases; physical bond for max magnitude of 9.5
Is an earthquake dimensionless?
Yes; it is on a log scale i.e. not linear
What is the magnitude (Mw) a function of?
, rigid of rock (G-shear modulus), area of rupture (Af), Displacement of rupture plane/horizontal
(Df)
Mo stands for?
Seismic movement= mxAxD(nm)
Mw stands for?
Movement magnitude= 2/3 (log10Mo)-6 & is UNITLESS
What is a main shock?
biggest shock out of a series
How long can after shock last for?
weeks or months
Does every event have aftershocks?
No
What zones have the largest earthquakes?
Subduction zones
How do you measure ground shaking?
seismometer and Mercalli Intensity Scale
What is a seismometer?
network of seismographs, typically mounted directly on bedrock and is often buried
What is the Mercalli Intensity Scale?
Scale of damage
Where do earthquakes occur?
along plate boundaries, subduction zones, rifting boundaries (diverge), collision convergent
How do earthquakes cause damage?
ground shaking, landslides, liquefaction, tsunami
What is liquefaction?
soil, like liquid and flows into pour space and separates grain
What is a tsunami?
only if the displacement of ground of ocean basin, only if land displaces down vertically, water
comes out to fill the space and flows back to shore as a giant wave
VERIFIED ANSWERS
Place of first rupture in an earthquake?
hypocenter or focus
The projection of focus to surface is?
epicenter
What is a surface wave?
seismic waves that travel along the earths surface
What are the types of body waves?
Non-directional; P & S waves; they are not confined to the earths surface, travel through earths
interior, both elastic
What is a P wave?
Primary wave. A body wave. generated by a sudden compression or extension of the ground at
the site of an earthquake, push or pull at a stretched spring
What is an S wave?
Secondary wave. generated by shearing or sliding motion at an earthquake site i.e. when rope is
shaken
What are the types of surface waves?
L & R waves
What is an L wave?
moves like a snake
What is an R wave?
up and down waves, comes from P waves, ripple effect
How is the size of an earthquake described?
its size and magnitude, Mw; it increases in value as amount of energy released during an
earthquake increases; physical bond for max magnitude of 9.5
Is an earthquake dimensionless?
Yes; it is on a log scale i.e. not linear
What is the magnitude (Mw) a function of?
, rigid of rock (G-shear modulus), area of rupture (Af), Displacement of rupture plane/horizontal
(Df)
Mo stands for?
Seismic movement= mxAxD(nm)
Mw stands for?
Movement magnitude= 2/3 (log10Mo)-6 & is UNITLESS
What is a main shock?
biggest shock out of a series
How long can after shock last for?
weeks or months
Does every event have aftershocks?
No
What zones have the largest earthquakes?
Subduction zones
How do you measure ground shaking?
seismometer and Mercalli Intensity Scale
What is a seismometer?
network of seismographs, typically mounted directly on bedrock and is often buried
What is the Mercalli Intensity Scale?
Scale of damage
Where do earthquakes occur?
along plate boundaries, subduction zones, rifting boundaries (diverge), collision convergent
How do earthquakes cause damage?
ground shaking, landslides, liquefaction, tsunami
What is liquefaction?
soil, like liquid and flows into pour space and separates grain
What is a tsunami?
only if the displacement of ground of ocean basin, only if land displaces down vertically, water
comes out to fill the space and flows back to shore as a giant wave
