Earthquake Review Flashcards
Magnitude
Measures energy of earthquake; doesn’t vary; uses seismograph
Intensity
Depends on population + building type; Mercalli Scale; Doesn’t use seismograph; varies
What does Mercalli scale measure?
Measures intensity; Depends on population and builidng type
Moment magnitude formula
Mo= NxDxA; N= Rock rigidity; D= Distance rock slip; A = area of fault
What would moment magnitude be used for?
More accurate; Used for larger earthquakes
Determine location of an epicenter from seismograph reading
- Determine lag time b/w P+ S waves; 2. Go to graph to find distance b/w epicenter + seismograph; 2. Plot center w/ distance radius; 4. Intersectio of circles = epicenter (triangulate)
What do circles represent
The distance the seismograph and the epicenter
Explain the Richter scale
Measures ground shaking/ energy; Designed for smaller earthquakes
How is the Richter scale sclaed
32x energy released; 10x amplitude
Primary Wave
Push/pull; compressional; Fastest; Body wave; travel through liquids + solids; Comressional
Secondary wave
travels only through solids; not liquids; Sharing waves -> up/down motion
Raleigh wave
Surface wave; Travel on surface; slow; similar to water waves; Rolling; Very damaging
Love waves
Surface wave; Very damagin; travel on surface; Horizontal shifting of surface; SLow
Mantle
Solid that flows; Mg+ Fe; P+S waves
Outer core
Liquid; Fe + Ni; P waves; NO s waves
Inner core
Solid; Fe + Ni
Normal fault
tensional stress; Divergent boundaries
Reverse/ thrust fault
compressional stress; Convergent boundaries; often create tsunamies; Usually has highest magnitude earthquake
Strike slip
Shearing stress; Often happen on divergent boundary
Divergent
Small earthquakes; shallow; normal fault
Ex of divergent
Iceland + mid-ocean ridge
Convergent
Most major earthquakes; Reverse faults; shallow through deep
Ex of Convergent
Japan
Transform
Shallow earthquakes
Ex of transform
San Andreas + Haiti
How an earthquake cn occur intraplate
Occur in middle of plate; Thought ot be ancient faults or the anthrospphere causing vertical movements; Ex: Haiti
Formation of tsunami
The displacement of water due to the power and energy gained from the subduction
What should you do during a tsunami warning?
Get to higher ground
Haiti earthquake
Most deady earthquake in W. Hemisphere; 7.0 magnitude; Transform
Chile Earthquake
Aftershock of Haiti; 8.8 earthquake; tsunami; Convergent
How are earthquakes predicted
Seismometer can be used to pick up vibration in Earth’s crust
How accurate in earthquake prediction?
Not very accurate
Liquefaction
Causes the ground to act like a liquid; Due to increased water pressure from earthquake waves
Is depth of earthquake related to its magnitude?
No
What type of boundary has deep focus earthquakes?
Subduction/ Convergent zones
