Trucks later this month will begin thumping the ground along Erie’s southern grass fields — and likely in the backyards of homes — in search for oil and gas reserves under the surface. That seismic testing will come ahead of Denver drilling firm Crestone Peak Resources’s plans to tap 30 wells in the area. An Erie email blast sent out this week says the work will finish sometime next month. A map released by the town shows a wide-ranging area where such tests will be conducted, though Crestone officials on Thursday said the majority of the work will be confined to land around Colo. 7 and East County Line Road, near the company’s planned Acme site at Colo. 7 and Bonanza Drive. “We’re trying to understand where we can access,” Crestone spokesman Jason Oates said Thursday, “and in order to more efficiently drill those wells we want to have a map of where we’re going.” Normally such work already would have been done at this point in the development process, he added, but the area’s relative dormancy in recent years and advancements in technology has made it necessary to revisit. Seismic surveyors place sensors roughly the size of soda cans across fields and neighborhoods at the star...