The P-waves have a speed of about 6 km/s. How do you estimate the average bulk modulus of Earth's crust given that the density of rock is about 2400 kg/m3. Answer the question in Pa?

Question

Earthquakes at fault lines in Earths crust create seismic waves, which are longitudinal (P-waves) or transverse (S-waves).

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Answer 1 · 2018-01-31T07:41:30

The bulk modulus is #=8.64*10^4MPa#

Apply the equation

#v_p=sqrt(M/rho)#

Here,

The density of the rock is #rho=2400kgm^-3#

The speed of the #"P-wave"# is #v_p=6kms^-1=6000ms^-1#

Therefore,

#M=rhov_p^2=2400*6000^2 (kg)/m^3*m^2/s^2#

#=8.64*10^10Pa#

#=8.64*10^4MPa#