Could the emptying of oil reserves cause land to sink, or earth quakes?

It depends where you dump it and how much of it you dump. Usually, a few thousand barrels of oil dumped in the ocean would cause water contamination. I have never heard of sinkholes appearing from dumping oil. I have heard that in sandy area, during an earthquake, the ground liquefies.Could the emptying of oil reserves cause land to sink, or earth quakes?
Yes, it can.





Removing oil, especially in areas that lack recharge sources such as groundwater, reduces the pore pressure of the formation. A reduction in pore pressure (that's the pressure of the fluid that's trapped in the formation, by the way) in most cases causes the formation to lose strength, and can cause minor displacement.


As for earthquakes, those are less likely, because rocks hard enough to fracture violently are unlikely to weaken much from oil removal.