At 5:04 p.m. last Tuesday, precisely a week after the devastating earthquake, church bells pealed throughout San Francisco to mark the city's survival and recovery. But a few churches declined to join in the commemoration, which had been requested by Mayor Art Agnos, because the reverberations from the tolling might have brought cracked belfries tumbling down. About 90 minutes after the clangor of the bells died out came the ominous rumbling of yet another aftershock, one of thousands that have done little discernible damage but are likely to keep rattling the nerves of residents for weeks.
The sequence was almost too...