We have all seen movies and news reports of mining disasters deep under ground, when cave-ins occur. Solid minerals have been extracted, deep voids have been left behind, and sometimes horrendous mining accidents occur when walls and ceilings collapse, killing miners, and leaving families and friend totally devastated.
That is not a pretty picture to remember is it? But what happens to the inside of the Earth when oil and natural gas is extracted? Often times this mining occurs deep under the ocean floor, as in the case with the Deepwater Horizon Oil Rig in the Gulf of Mexico. In September 2009, the rig drilled the deepest oil well in history at a vertical depth of 35,050 feet (10,683.2 m) and measured depth of 35,055 feet (10,685 m).
I remember a saying from my younger years that seems appropriate to this line of thinking:
‘Nature abhors a vacuum’.
This saying is used to express the idea that empty or unfilled spaces are unnatural as they go against the laws of nature and physics.
So the question begs asking – can drilling for oil cause earthquakes?
Important Disclaimer: I am NOT a geologist, simply a curious spectator asking deep questions.
I went looking on the internet for answers. As is sometimes the case, it left me with more questions than I began with, and there are many points of view on this particular question.
While disagreement abounds on this topic, scientists at the U.S. Geological Survey (USGS) say that oil production can cause earthquakes, but not the kind reported in the news.
According to the Rigorous Intuition, some earthquakes, such as the 2004 quake that triggered a deadly tsunami in Sumatra, occur at plate boundaries where hard, rocky slabs slide against each other to release tremendous amounts of energy. Oil generally is found in permeable sediments that are soft and squishy, not in hard rock. When this squishy land moves, it releases a small amount of energy, which can lead to a “mini-seismic event”-one that is barely detected on the Richter scale.
Here’s how it works: With high-tech equipment, oil companies pinpoint oil-rich areas and use large drills to puncture the surface below the sea, sometimes as deep as 10,000 feet. As this pricey fluid gets sucked from the sediment pores, the surrounding rocks shift positions to fill in the newly vacated spaces. At a large scale, for example the volume displaced when millions of barrels of oil are produced, the land movement can actually cause a mini-seismic earthquake, according to Robert Morton, a USGS coastal geologist.
Another search provides different information which is also worth considering.
In 1958, a geologist calculated that injecting fluid into the ground increases the chance of earthquakes. Thirty-one years later, another geologist has shown the reverse: or oil out of the ground can also trigger earthquakes. Pumping out underground crude contracts the rock in oil reservoirs and sets up large pressure changes over short distances, Paul Segall of the U.S. in Menlo Park, Calif., calculates in the October GEOLOGY. Vertical contraction makes the ground above the reservoir sink, while horizontal stresses pull surrounding rock inward. If the pull becomes strong enough to shear the rock, an earthquake results.
Although geologists have reported mild, shallow earthquakes near gas and oil fields since the 1920s and have long suspected the wells as the cause, Segall’s mathematical analysis shows specifically how and where the ground slips, says geologist C. Barry Raleigh of the University of Hawaii in honolulu.
Segall’s ground-breaking work, Raleigh adds, represents “a messy problem neatly tied up.” “This is the first time that anyone has shown in any kind of analytical way that withdrawing fluid causes earthquakes,” confirms John D. Bredehoeft of the USGS.
Because such quakes seem limited in magnitude, petroleum engineers probably won’t change their techniques, Raleigh says. But they may apply Segall’s work to squeeze more fuel out of wells.
Underground reservoirs often consist of fractured rock surrounded by fluid. Pumping the fluid can collapse the fractures, sealing off the remaining reservoir. Segall’s analysis could be used to forestall this collapse, Raleigh says.
Independent Senator Dr. Ron Paul even had questions about oil drilling and the Haitian earthquake (on his blog), and pointed me to information in Ezili Danto’s Blog. Dr. Paul is just one of many who had similar questions. Do a Google Search it is quite illuminating.
TO SUM UP:
There seems no consensus as to IF undersea mining (mining in general) can cause fault lines to shift and possibly cause earthquakes. Reading through the various sites referenced below leads one to imagine that as oil company’s pump out our precious reserves, they automatically pump in water, albeit it for commercial reasons, to flush out further oil supplies – while at the same time, filling the cavities and (?) equalizing the pressures.
Fill the cavities with seawater and HEY PRESTO you have no vacuum…. Remember nature abhors a vacuum!
However I do have a question in this regard as to by whom, what or how is this void currently being equalized in the Gulf of Mexico’s disaster?
The Oil Rig has gone! The pipe line is severed and punctured in several places and is gushing (how many gazillion) barrels of oil per day into the Gulf of Mexico.
Meanwhile the pressures in the undersea oilfield are not being equalized by the means usually employed by the oil companies.
As far as we have been told there is only one pipeline going to that depth, and it has been severed at the top.
Sadly right now I have little faith in what oil company’s have to say, and not much more in what the EPA and other Government bureaucracy’s are telling us.
It pays to keep seeking and searching and discovering what else is there for the finding.
YES they do know that drilling can cause seismic activity. You just don’t find this information on the front page of the New York Times or the Sydney Morning Herald.
Drilling is NOT an exact science!
“Deepwater Horizon Drills World’s Deepest Oil & Gas Well”, Transocean press release
Oil Extraction Stresses Earth, Contributing to Earthquakes and Tsunamis