NEW YORK (MarketWatch) -- TGC Industries Inc., the Plano, Texas, provider of seismic data, reported that second-quarter net income rose 15% as revenue more than doubled. Net reached $2.1 million, or 13 cents a share, from $1.8 million, or 14 cents, in the year-earlier period. Shares outstanding rose 20% to 15.7 million. Revenue was $14.9 million against $7.2 million. The revenue jumped stemmed from a rise to seven field crews in operation in the latest period from three crews a year earlier, as well as productivity improvements, TGC said. The quarter was hurt by persistent rain in south Texas and Kansas in May and June, which hampered crews there, TGC said. Demand for its services remains "strong," it said. TGC shares fell 33 cents, or 3.1%, on Friday to $10.27.