earthquakes reflection 3- studying and measuring earthquakes

magnitude

scale of amount of energy released

intensity

relative scale of effects felt by people and structures

mercalli scale

intensity, no reference to faults or math, subjective, I-XII

magnitude scale

logarithmic scale, seismic measures, great = >8, minor = <3.9

great/megathrust

8.0 or greater

hazards associated with earthquakes

building collapse, debris falling, highway/structure collapse, water and gas mains break, landslides, sinking buildings, changing topography, tsunamis

major earthquake

7-7.9; IX-X

moderate earthquake

5-5.9; VI-VII

minor earthquake

<3.9; <III

strong earthquake

6-6.9; VII-VIII

great earthquake

>8; X-XII

light earthquake

4-4.9; IV-V

earthquakes >8.5 usually occur

at subduction zones