In the search for more sources of fossil fuels, the process of hydraulic fracturing – commonly called “fracking” – has led to a tremendous increase in U.S. crude oil production. That’s the good news.
The downside of employing this new oil-production technology is that the fracking process has led to an increase in what we call “manmade” earthquakes. We’re not making an eco-political statement here … that’s the findings of semiologists who study fracking.
In a 2015 report by the Seismological Society of America (SSA), they addressed a direct correlation between increased fracking activity and earthquakes felt in Ohio. They suggest that “close cooperation among government, industry and the scientific community” is important as operations expand and there is the potential to disrupt pre-existing faults. 
What many don’t know is that there is another source of manmade quakes: the disposal of wastewater from regular oil and gas production. In Oklahoma, they now experience more earthquakes than the state of California. According to the U.S. Geological Survey:
Only a few of the over 2000 magnitude 3 and larger earthquakes since 2009 that have occurred in Oklahoma have been connected to hydraulic fracturing. The majority of earthquakes in Oklahoma are caused by the industrial practice known as "wastewater disposal". Wastewater disposal is a separate process in which fluid waste from oil and gas production is injected deep underground far below ground water or drinking water aquifers. In Oklahoma over 90% of the wastewater that is injected is a byproduct of oil extraction process and not waste frack fluid.
To take a quick step back, “Hydraulic fracturing, informally referred to as “fracking,” is an oil and gas well development process that typically involves injecting water, sand, and chemicals under high pressure into a bedrock formation via the well. This process is intended to create new fractures in the rock as well as increase the size, extent, and connectivity of existing fractures. Hydraulic fracturing is a well-stimulation technique used commonly in low-permeability rocks like tight sandstone, shale, and some coal beds to increase oil and/or gas flow to a well from petroleum-bearing rock formations. A similar technique is used to create improved permeability in underground geothermal reservoirs.”
A byproduct of this process is ‘flowback’ or wastewater – which is a mixture of fracking fluid and formation water which contains high levels of brine (salts), toxic metals and radioactivity. While in some areas up to 70% of this this fluid is recycled and reused, the additional liquid is injected deep into underground wells. According to the United States Geological Survey (USGS) agency, wastewater disposal is the primary cause of the recent increase in earthquakes in the central United States.
Bottom line: The range and scope of seismic zones in the United States have now vastly expanded from what we traditionally think they are – such as the San Andreas Fault in California, the Yellowstone Basin, and the New Madrid Fault centered in Missouri.
Ok, so now that we’re done with the fracking lesson – I bet you’re wondering what this means for you and your building.
Because a lot of fracking is occurring in the central US – a traditionally non-seismic area – we’re starting to see earthquakes and tremors in areas that haven’t experienced them in the past which means their buildings and expansion joints weren’t built to withstand this new range of seismic movement.
It is important that architects and structural engineers are included in those conversations so they can prepare buildings to withstand stronger seismic events – a crucial component to this is wider expansion joints.
Architectural expansion joints are designed gaps within a structure to absorb thermal and seismic movement. They allow for the contracting and shifting of a building during these daily and severe experiences.
Non-seismic areas are traditionally designed with smaller joint widths because they only need to withstand the expansion and contraction caused by daily thermal movement. If these buildings suffer a large seismic event, it could lead to structural damage and increased danger for those inside.
As more information is released regarding growing seismic activity, we must change our building practices to accommodate a wider range of movement where necessary. For more information regarding architectural expansion joint systems and the role they play in your building, download our free whitepaper, 6 Questions Architects Should Ask About Expansion Joints.