Yes, it has been established in some states that drilling and the process known as "Fracking" or removing the oil from shale rock by high pressure hoses, causes minor earth quakes. A study by Department of Energy ordered by congress, showed this to be factual and also dangerous in harming purity of water reserves beneath the ground.Most quakes are usually minor and no larger than around two to three on the scale of measurement for earthquakes. The great melting and deluge of fresh water from melting glaciers and ice in arctic regions and around the world creates much more weight and pressures on the geographic structure beneath and this may lead to much larger earth quakes, as we have witnessed in recent years around the globe. Another possible cause of some earth quake activity in the past may well have been the result of nuclear testing of underground bombs and the cause of more severe seismic activity over the years. Natural volcanic eruptions, movement of underground magma, and sliding of the earths crust has been attributed to most quakes. The many fault lines around the world are surprising in number and most are carefully monitored. It is hard to imagine that the earth, spinning on its axis and about the sun in such extreme speeds, and being composed of such fragile materials, being pulled upon by the moon circling about it, as well as gravitational forces from other planets, would not have earth quakes in such numbers.