A sharp rise in the number of earthquakes in Oklahoma, apparently related to underground disposal of wastewater from oil and gas production, has significantly increased the chances that a damaging quake will occur there, federal and state scientists say.

Already this year there have been 145 small earthquakes of magnitude 3.0 or higher in the state, compared with 109 for all of 2013, the scientists with the United States Geological Survey and the Oklahoma Geological Survey said in a statement Monday.

The quakes, largely in the central and north-central parts of the state, have rattled nerves but caused little damage. But the increase makes it more likely that a quake of magnitude 5.5 or higher could occur, the scientists said, although they did not quantify the increased risk.

They said they were issuing the advisory so that it might become a “crucial consideration in earthquake preparedness for residents, schools and businesses.” Of special concern, they said, were older masonry structures, which could be heavily damaged by earthquake shaking.