article_snippet.sent: Many faults awakened by drilling have not moved in millions of years, the Oklahoma Geological Survey geophysicist William Ellsworth said. '
article_snippet.sent: Many faults awakened by drilling're ancient faults,' Geological Survey geophysicist William Ellsworth said. '
article_snippet.sent: Many faults awakened by drilling don't always know where Many faults awakened by drilling are.'
article_snippet.sent: The industry group has said efforts are made to map fault lines where drilling occurs.
highlights_snippet.sent: Many of faults awakened by drilling have not moved in millions of years .