Los Angeles' all-news radio stations rolled into action minutes after a strong aftershock early Sunday to last week's 6.1 temblor. The stations suspended normal programming and commercials for earthquake news and reports. At KFWB (980), three reporters offered live reports from the ground and another reporter from a helicopter, according to news director Bill Yeager. KNX-AM (1070) had a reporter at Caltech within 10 minutes of the aftershock "because he lived close by," according to news editor Debbie Wright, who said finding available reporters wasn't tough. "They know they're on standby as soon as they feel it." This week, KFWB will re-air an updated version of Jack Popejoy's recent series on earthquake preparedness hourly at seven minutes after the hour. The updated version will include all information about the most recent quake, including Sunday's aftershock.