TULSA — A state seismologist expert presented data Wednesday that showed a direct relation between the increased volume of wastewater injected into disposal wells and higher numbers of earthquakes while oil production remained level. The data showed corresponding decreases after state regulators stepped up regulation of wells into which oil and gas companies inject billions of barrels of wastewater produced during the drilling and extraction processes. “Horizontal drilling has changed everything,” Oklahoma Corporation Commission spokesman Matt Skinner said. “That is what has led to the use of injection wells for wastewater.” Skinner was one of five panelists who spoke Wednesday during a public forum at the University of Tulsa. The event, sponsored by the Tulsa Section of the American Chemical Society, attracted more than 200 people.