Sunoco recently offered to temporarily relocate residents of Lisa Drive, where drilling for the Dragonpipe (Mariner East 2 pipeline) caused sinkholes. These sinkholes endangered the 80-year-old ME1 pipeline, which was already in operation and sending limited quantities of NGLs  to Marcus Hook.

Sunoco is offering to put the affected homeowners up in a hotel for 4-6 weeks. The letter sent to them provides no real reason for the offer. It simply says that “…small excavations will be completed approximately every 35 feet along the ME-1 pipeline area to confirm pipeline location and to install markers for reference during additional geotechnical studies”. It adds: “Also during the week of April 2-6, geotechnical data collection activities will begin, including the use of small auger drills to obtain core samples to identify subsurface voids, if any, in the area.”

Hmm. The generous offer is unlike Sunoco’s previous behavior toward homeowners. It certainly can’t be because Sunoco wants to protect them from the noise of the “small auger drills”, which will presumably be far less than the noise of the HDD drills to which dozens of homeowners have already been subjected. The fact that Sunoco’s tests are “including” small auger drills suggests other activities will occur. So the real reason Sunoco wants the residents gone is not clear.

But there is evidence to suggest that seismic testing is the reason.

Making the earth shake. Seismic testing involves various methods of sending sound waves through the earth and determining how quickly they travel. It can detect the nature and location of underground rock, water, voids, and pipelines. That could be what Sunoco plans to do. Sunoco writes that it “has completed preliminary geophysical investigations” and that it will now do “additional geotechnical studies”. The terms “geophysical” and “geotechnical” aren’t explained, but seismic testing would fall under them.

In fact, Sunoco is probably required to do seismic testing. The Emergency Petition that initiated the shutdown contains the following language: “Sunoco shall perform the necessary geo-physical tests and analyses, including but not limited to, i) Resistivity, ii) Seismic, iii) Gravity on the HDD project at the Lisa Drive site from the bore beginning to end…”

thumper truck
Vibroseis truck (“thumper truck”). Photo source: Wikipedia

Seismic testing requires making the earth vibrate, and there are two common ways to do that. One is using vibroseis trucks or “thumper trucks”. The other is using small explosive charges lowered into holes that are drilled for the purpose. Both are effective ways of making the earth shake. The industry claims these techniques are completely innocuous, and they could be right, but there are many cases of companies being sued for damages alleged to be caused by seismic testing.

For example, here is an article about 124 complaints by homeowners in a small Texas town about damage alleged to be from seismic testing. The damage was real enough, including “…interior and exterior damage to homes such as sheet rock cracks, cracks in exterior mortar brick, plumbing leaks, broken shower tiles, cracked driveways, separation of interior hardwood, foundation damage, cracked sidewalks and ceiling cracks”. But was it due to the seismic testing?

The company involved claimed the damage was due to other factors, such as the drought that occurred at the same time.

Google turns up many other reports of damage from seismic testing, including damage to sewer lines. It makes me wonder: could seismic testing damage an 80-year-old oil pipeline?

Of course, in the case of Lisa Drive, I have no idea whether seismic testing is the reason Sunoco wants the residents out. It’s just speculation on my part. For now, it is the best theory I can come up with.