CLEVELAND (Reuters) - Ohio voters by a wide margin want a halt to hydrofracking until more impact studies are conducted, though they believe there are economic benefits to drilling for natural gas and oil, a Quinnipiac University poll released on Thursday found.

The poll comes just weeks after Ohio ordered the shutdown of five wells around Youngstown that accept waste materials from the fracking process, after a series of earthquakes that could be related to their operation.

Seventy-two percent of voters polled said there should be a halt in hydraulic fracturing, or simply fracking, in Ohio until more was known about the impact of the process, Quinnipiac found. Fracking uses massive, high-pressure injections of water, chemicals and sand to release trapped oil and gas.

Sixty four percent of respondents supported drilling for natural gas and oil because of the potential economic benefits to Ohio, and 29 percent opposed drilling due to the possible environmental impact.

"They recognize the economic value of drilling for fossil fuels in the state, but are worried about potential environmental risks of the specific technique -- hydro-fracking," said Peter Brown, assistant director of the university's polling institute.

Quinnipiac University surveyed 1,610 registered Ohio voters from January 9 to January 16 for the poll, which has a margin of error of 2.4 percentage points.

Youngstown has experienced 11 earthquakes since the wells started using extremely high-pressure injection to force the waste materials into permeable rock, the latest on December 31.

Scientists monitoring the seismic activity in the Youngstown area found that the last two earthquakes were near the same depth and location of a disposal well. Since the shutdown, material has been removed from the well to relieve pressure.

State officials have not yet decided whether the wells will be shutdown permanently.

Fracking is widely used in the oil and gas industry and has sparked controversy in other parts of the country including in Pennsylvania, where it is used in natural gas exploration.

(Editing by David Bailey and Greg McCune)

Mochila insert follows...