Why are all intermediate- to deep-focus earthquakes generated at convergent plate boundaries? What ...

The convergent plates generate compressional forces as a result of plate subduction. The down-going
plate undergoes phase changes as it descends into the mantle.

Shallow-focus: less than 70 kilometers; intermediate-focus: between 70 and 300 kilometers; deepfocus:greater
than 300 kilometers

Earthquakes do more damage in places where the population density is high and the structures are not
especially well built. More people are killed if they are out on the road and at work than if they are
home in bed.

Continental crust is complex, consisting of all rock types, but is usually described as granitic. It
averages 35 km thick. Oceanic crust is comparatively simple, consisting of gabbro in its lower part and
overlain by basalt. Its thickness ranges from 5 to 10 km.

P-wave velocity abruptly decreases, and S-waves disappear, meaning that at least the outer core must
be liquid