MADRID (AP) -- Thousands of Spaniards on Sunday protested the presence of an underground gas storage plant over growing fears it is triggering minor earthquakes in the area.
Initial police estimates said some 3,000 people had gathered to carry banners along the seaside promenade of the coastal town of Les Cases d'Alcanar, 500 kilometers (310 miles) east of Madrid, calling for the offshore plant to be closed or dismantled. But protest organizers said 6,000 people marched, chanting, "We don't want it. We live off fishing and tourism."
Spain's Geographical Institute has measured a sharp increase in temblors — 139 in the 10 days up to Saturday — since operators began pumping gas into the facility. Some earthquakes have exceeded magnitude 4.0. The first alarms were set off on Sept. 13 after 300 quakes were detected.
"Some weeks after we began to inject gas, the earthquakes began," said Recaredo del Potro, president of Escal-U.G.S., the company in charge of the project.
Injections stopped on Sept. 16, Del Potro said in a TV interview by state broadcaster TVE, and the government banned further injections two weeks ago.
However, the institute has continued to detect tremors, and on Thursday the regional prosecutor's office opened an investigation into the plant and flew inspectors to a platform atop the storage facility to determine if pumping had indeed been halted. Press reports said they had.
Jose Manuel Soria, Spain's industry minister, said Thursday that there appeared to be a direct link between the quakes and injections of gas into rocks that form part of the underwater storage system, which was intended to serve the eastern Valencia region as a supply of fuel gas that is used to generate electricity and for domestic heating and cooking.
The project is estimated to have cost some 1.3 billion euros ($1.8 billion), with half of the funds provided by a consortium of nine banks and the remainder by the European Investment Bank, TVE said.
The tremors are occurring just off the coast of Castellon city and Les Cases d'Alcanar, an area Spain's College of Geologists said is not known for such seismic activity.