Tekla Perry writes: Earthquake alert systems that give a 10 or 20 second warning of an impending temblor, enabling automatic systems to shut down and people to take cover, are hugely expensive to build and operate. (One estimate is $38.3 milllion for equipment to span California, and another $16.1 million annually to operate.) But a Palo Alto entrepreneur thinks he's got a way to sense earthquakes and provide alerts far more cheaply and with much greater resolution. And he's got money from the National Science Foundation to begin the first test of his system — covering the Bay Area from Santa Cruz to Napa and the cities of Hollister, Coalinga, and Parkfield. He starts that test next month.