SEISMOLOGY: SEISMOS: (Greek Word) - Shaking LOGUS: (Greek Word) Science or treaties So Seismology -> The study of shaking of earth
Seismology is the branch of Geophysics
concerned with the study and analysis of Earthquakes and the science of energy
Waves on a String
density
Newtons law of motion
Tension force
This is one dimensional scalar wave equation propagating with velocity, v
A simplified case for the wave equation is the plane wave propagating in the x-direction. In this case, the wav
i1
1 , 1 , 1
2 , 2 , 2
i2
Observe that when waves travel from a solid of one velocity to different velocity, the direction changes. This has a large impact on the nature of seismic waves, since the Earth is highly variable.
i1
1 , 1 , 1
2 ,
Seismic Moment and Stress
Aki (1966) introduced Mo Is the product of three factors that indicate the size of the earthquake:
Mo=(shearmodulus)x(rupturearea)x(slipoffset)
For crustal rocks =1011 3.3 dyne/cm2 Seismic moment (M) is measured in N-m