Earthquakes in GTA? Yes, I am kidding. But what if a 4.65 magnitude nuclear explosion occurred at 3km deep underground secret lab, located close to the junction of Kirby road and Kipling Ave, Northwest of Vaughan (see google).

Here is a terrain map of the location. The black star indicates the hypocentre location.

Using SPECFEM3D with P=5, grid interval= 200m, half duration 0.2 second (frequency ~2~3Hz), the computation on my 18 core cluster took 1.5 hours. Here are some snapshots:
T=1.5 second

T=2.5 second

T=4.0 second

Notice the converted shear wave distribution behind the P-wave front? At some locations, the shear wave energy is amplified by the local topography and can severely damage the local surface structures. Good news: the modeled topography is 10 times amplified from the real topography. So the results here have little indication to the real case.

Coming soon:
Parallel hybrid spectral element and finite element simulation of airborne electromagnetic survey over a heterogeneous earth model with multi-scale lossy objects. Stay tuned.