What causes earthquakes and tornadoes?

Answer 1

The formation of tornadoes is complicated.

First, a condition called wind shear, in which the speed or direction of the wind changes with altitude. If the shear is strong enough it can essentially tilt a thunderstorm, this separates the updraft and downdraft of the thunderstorm, preventing them from interfering with one another. This allows the storm to become stronger and last longer.

Additionally, if the wind shear is strong enough it can start the air rolling in what is called horizontal vorticity. This horizontal vorticity can then be turned vertical by a thunderstorm's updraft. When this happens, the thunderstorm may start rotating. The rotation is especially strong in an updraft called a mesocyclone. If the storm intensifies rapidly enough, a relatively warm downdraft called a rear-flank downdraft or RFD can wrap around the bottom part of the mesocyclone. This can then tighten and intensify its rotation and bring it down to the ground to produce a tornado.

Earthquakes can have a number of causes, but most occur as a result of tectonic plates sliding past or across one another. As the plates move they often snag on each other, but will still be pushed along by underground forces. As a result, stress builds up until finally the plates slip and the stress is released in the form of seismic waves. Stress can also build up withing plates are weak spots in the crust. Some of these areas are old plate boundaries. Earthquakes can also be triggered by volcanoes as magma moving underground creates cracks in the rock.