# Geology 1 MT2: EQs

 earthquake the sudden slip on a fault (release of elastic energy) and the resulting ground shaking and radiated seismic energy caused by the slip hypocenter (focus) the first point on a fault that moves in an EQthe EQ originated at the hypocenter epicenter the point on the earth's surface that is directly above the hypocenter rupture area the portion of a fault that slips in an EQ surface trace where the fault breaks the earth's surface blind fault a fault that does not break the earth's surface elastic rebound theory 1. stresses (force/area) are applied to a fault2. strain (deformation) accumulates in the vicinity of friction-locked faults3. strain accumulation reaches a threshold and fault slips suddenly4. rupture (slip) continues over some portion of the fault 2 types of seismic waves body waves - move through the earth's interiorsurface waves - through earth's surface 2 types of body waves p-wave: (primary wave) the first wave to arrive following an EQpropogate by alternately compressing/expanding materialcan move through solids, liquids, gases s-wave: (secondary wave)shear wavecan only move through solids 2 types of surface waves Love wave: horizontal shearing of the earth's surface Rayleigh wave: "rolling" of the earth's surface calculating the distance to an EQ depends on the time gap b/t p-waves and s-wave arrivals (∆ t) ∆ t = ts - tp [ts= s-wave arrival time, tp= p-wave arrival time] D= (Vp x Vs) / (Vp - Vs) x ∆ t what is Richter magnitude based on? the amplitude of the largest s-wave 4 steps to find Richter magnitude: Find distanceMeasure amplitude and find logFind log A0 from graphFind difference: ML= logA - logA0 A fault that has both horizontal and vertical offset oblique fault Fault that moves without an EQ fault creep Authorkjel ID80826 Card SetGeology 1 MT2: EQs DescriptionGeology 1 MT2: EQs Updated2011-05-09T17:06:31Z Show Answers