NU Online News Service, April 5, 10:43 a.m. EST
In the wake of the 7.2 magnitude earthquake that struck Baja California, Mexico, there were no immediate reports of damage from San Diego or Los Angeles, but inspections of buildings and infrastructure are underway, a catastrophe modeling firm said.
The Easter Sunday quake, according to Risk Management Solutions in Newark, Calif. had an epicenter 16 miles southwest of Guadalupe Victoria and 104 miles east-southeast of Tijuana, Mexico.
Mehrdad Mahdyiar, director of earthquake hazard at AIR Worldwide catastrophe modeling firm in Boston said the rupture started about 38 miles southsoutheast from Mexicali, Mexico about 40 miles from the Mexico-U.S. border before moving northward, "Shaking was felt as far away as Los Angeles, Phoenix and Las Vegas." he reported.
Neither AIR or RMS issued an immediate insured loss estimate.
U.S. Geological Survey warned that an aftershock of 6 magnitude is likely in the next few days. The USGS listed the event as the largest earthquake to strike in the area since 1892.
Power outages in southern California from the quake are reported to have affected more than 5,300 customers, said RMS. At a San Diego hotel guests were evacuated after cracks were found in the floor.
Mexicali, the closest city to the epicenter, with a population of close to 600,000, seems to have been subject to a very strong shaking of intensity VII, RMS said.
That level of shaking, the firm explained, has potential to cause moderate damage to resistant structures and moderate to heavy damage to vulnerable structures.
Rescue teams were reported to have been deployed in Mexicali. In Tijuana, with a population of around 1.3 million, shaking was estimated by the USGS to have been at the moderate level of intensity V.
RMS noted that damage reports were very sparse with power outages said to be widespread at. Two fatalities and at least 100 injuries were reported in Mexicali.
The USGS 'Did you Feel It? Intensity Map' indicates that the shaking was felt throughout southern California and southwest Arizona with shaking of intensity IV (light) to VI (strong) reported throughout these areas.
Mr. Mahdyiar at AIR described insured residential properties in Mexico as mostly consisting of unreinforced masonry surrounded by a thin reinforced concrete shell with commercial properties tending to be constructed of confined masonry or reinforced concrete.
"Depending on the level of earthquake resistant design implemented and the age of the buildings, some damage to beam-column connections, walls, and to other structural elements can be expected in areas close to the epicenter," he explained
AIR said currently, a single national building code for structural design does not exist in Mexico and enactment and adoption of building codes are subjected to the government department in each of the more than 2,400 municipalities.
Mexicali's older unreinforced masonry buildings, many built in the 1930s and 1940s, have not been retrofitted for ground shaking, AIR noted. The firm said large cracks are apparent in some walls, making the possibility of collapse from aftershocks a concern.
In El Centro, about 7 miles to the north of Calexico, the damage seems to have been restricted to shattered shop front windows and some collapsed ceilings, AIR said.