Mexico border on Sunday shook high-rises in downtown Los Angeles and San Diego and was felt across Southern California and Arizona. Caltech and the U.S. Geological Survey says the 7.2 magnitude quake struck Sunday at 3:40 p.m. in Baja California, Mexico, about 19 miles southeast of Mexicali, at an area that has been hit by magnitude 3.0 quakes all week.

The earthquake rattled buildings on the west side of Los Angeles and in the San Fernando Valley, interrupting Easter dinners. Chandeliers swayed and wine jiggled in glasses. Tremors were felt as far away as Phoenix. There were no initial reports of damage in the San Diego area.

Emergency services in both the U.S. and Mexico scrambled to assess the extent of casualties and damage, including fallen buildings, buckled roads, cracked water canals, fires and telephone and electrical outages. It appeared that most of the damage was in the twin border cities of Calexico, Calif., and Mexicali, Mexico, where at least two people were reported killed and several injured.

Witnesses on both sides of the border reported feeling a strong, rolling series of shakes that unleashed panic in a dozen or more towns and cities. Families in the middle of Easter lunches were sent running for cover.

“It’s really ugly here,” Olga Jimenez, 29, a water-company worker in Mexicali, said by telephone as her house continued to shake around her and ambulance and police sirens wailed in the background. “We felt a really big shake. The walls on houses fell down and people were running in the streets screaming.”

A new four-story parking garage at Mexicali’s state government headquarters partly collapsed, along with part of the city’s courthouse, residents said. Patients were evacuated from the main hospital for fear of structural damage.

At least one person was killed in Mexicali by falling debris, Alfredo Escobedo, head of local emergency services, told reporters. A second man was killed when he panicked as the ground shook, ran into the street and was struck by a car.

Miguel Coronado, 48, who was in Mexicali with half a dozen relatives visiting family for Easter, said the quake “shook so strong that some people fell down. Some people got hysterical, and others started praying.”

On Sunday night he joined a flood of people walking over the border from Mexicali into Calexico, after the crossing was closed to northbound vehicular traffic. People streamed across carrying babies, lugging laundry bags and pushing suitcases and elderly relatives in wheelchairs.

“It’s a disaster over there,” said Nayeli Ramirez, 17, after crossing into Calexico. “Buildings are tipped up. Cars are smashed. It’s horrible. Everyone is running.”

After 16 years and $10 billion—and a long morning of electrical groaning and sweating—there was joy in the meadows and tunnels of the Swiss-French countryside Tuesday: the world’s biggest physics machine, the Large Hadron Collider, finally began to collide subatomic particles.

The $10-billion structure at Geneva collides particles at three times previous energy levels. It hopes to find smaller particles and make other physics discoveries.

The Large Hadron Collider in Geneva succeeded early Tuesday in colliding subatomic particles at three times the highest energy levels previously recorded.

Scientists gathered in a room at Caltech and in similar groups around the globe witnessed the achievement at 3:58 PDT.

“There were cheers in all the control rooms,” said Caltech
physicist Harvey Newman. “As soon as we get the data, we’re analyzing it … it’s been a long time coming.”

Researchers were waiting for the promised flood of data that would come as protons from two particle beams from the 17-mile-circumference collider smashed into each other.

Several experiments using the particle accelerator could help test for smaller particles, dark matter, other dimensions, supersymmetry and other theories in particle physics, researchers said.

“We’re pretty happy because we’ve been waiting all night,” said Andy Yen, 21, a senior who had worked on experiments related to the collider for most of his undergraduate career. “Some people have been waiting 15, 20 years – it’s late, but it’s worth it.”

Earlier that night, two previous attempts to ramp up the accelerator had been cut short, and the researchers, who at peak attendance numbered two-dozen-plus, were running low on pizza and energy. The buzz of conversation between professors and doctoral candidates died down each time the two beams were spun in preparation for the planned collision.

Many said they had planned stay all night until the data began to flow in, even though they would not have immediate access to the measurements. Caltech particle physicist Bertrand Echenard said he was staying for the experience.

“When you watch the Olympic Games, you can watch the flame for 15 days, but what you want to watch is the torch lighting,” Echenard said, standing below two clocks: one with “GENEVA” pasted over the glass, a second covered in “CAL TECH.”

“It really is the start of something.”