As San Franciscans prepare to celebrate the centennial of the city's triumph over the great earthquake and fire of 1906, we are reminded by events in the aftermath of Hurricane Katrina of the darker side to such cataclysms.

When San Francisco Mayor Eugene Schmitz made his way down Market Street on April 18, 1906, on the morning of the disaster, he observed saloons in full swing and evidence that looting had already taken place. He ordered that all alcohol sales be suspended.

Army Gen. Frederick Funston, realizing that the disaster was beyond the ability of city officials to deal with, immediately -- and on his own initiative -- ordered 2,000 troops from the Presidio into the city to maintain order. Mayor Schmitz issued a written proclamation later that day declaring that looters should be shot on sight.

The first looter was shot while trying to break into Shreve's Jewelry Store at Post and Grant streets at 10 a.m. on April 18. During the next few days, according to official counts, nine men were shot by military and volunteer forces. Not all were looters.

A relief worker returning from a visit to his family in San Mateo with a Red Cross flag prominently displayed on his automobile was shot dead by a group of volunteers at 22nd and Guerrero.

Joseph Mayer, superintendent at the Children's playground, was killed by a National Guard corporal at Eighth and Harrison streets in what appears to have been an altercation about whose authority should prevail.

A retired National Guard captain killed a man carrying a chicken -- the captain incorrectly thought it was stolen -- at Lombard and East Street (now the Embarcadero). Frank Riordan was shot and killed on Cedar Street by a National Guardsman with whom he had a verbal confrontation.

Cadet Irvine Aten, who had come from Berkeley with the UC Cadet Corps to help with relief, was shot by a drunken soldier at Polk and Eddy streets, but he survived. Police Officer John Alpers was shot in the arm by a group of volunteers when he questioned their authority to carry firearms.

Some reports were exaggerated. One survivor claimed that 10 looters had been shot at the Shreve's break-in. A contemporary Oakland Tribune account of 14 killed while attacking the Mint at Fifth and Mission is known to be false.

Still, it's probable that substantially more were killed than official counts recorded.