In March the Basque terrorist group ETA threatened to target tourist resorts in its bombing campaign to wrench an independent homeland from Spain, and made good on its threat Aug. 18 with a powerful car bomb outside a hotel in the popular Mediterranean resort of Salou, about 55 miles south of Barcelona. Thirteen people were injured. Two days later a grandmother was killed and her toddler grandson seriously injured by another ETA bomb in San Sebastian. These incidents followed several others, including the defusing of two bombs in San Sebastian Aug. 16, a bomb that temporarily closed the high-speed rail link between Madrid and Seville Aug. 15, a large car bomb at Malaga airport on the Costa del Sol last month and an explosion that killed the ETA bomb handler in the resort town of Torrevieja. While the chances of being in the wrong place at the wrong time to be injured by a bomb are slim, ETA incidents are on the rise.