A Rip in the Desert Canvas

The spot where the Hector Mine quake rumbled to the surface is marked by a gash in the earth that sent a cobweb of cracks across the hardscrabble ground as if it were an Easter egg shell.

It sits on this remote plain, which is usually only seen by bomber pilots from the Marine base at Twentynine Palms.

But the Marines took a break from war games Monday, two days after the 7.1 quake, allowing scientists to map and study the fresh rupture.

With sunset as their deadline, field geologists concentrated on the parts of the 25-mile rupture line that wound through delicate alluvial plains where tank tires and even wind could soon destroy the telltale clues of the quake.

Geologist Scott Lindvall hurried his three-man team along, splitting his attention between a tape measure and the fading day. The team was working under the direction of the U.S. Geological Survey.

“We’ve got to get these measurements before it gets dark,” he said. The ridge they were following, from which the ground abruptly dropped off about four feet, was not there before the earthquake.

The epicenter was about four miles to the east, somewhere in the rust-colored granite of the Bullion Mountains. It would have to wait. Scientists figured that tougher terrain could better stand up to the next three days of military maneuvers.

That night at a McDonald’s in Barstow, exhausted team members gathered to exchange information. Over Big Macs and mango shakes (an appropriate orange for upcoming Halloween) they floated theories and handed in data.

The mysteries they hope their measurements and calculations will help to illuminate are myriad:

What are the characteristics of the fault? Are there other little-noticed faults like it that could pose a threat? How much did the earth slip? In which direction? Is this part of a cluster of quakes in the Mojave? When was the last earthquake on this fault, long thought inactive?

And as always, the granddaddy question of all: Was there any way to have predicted this?

*

For scientists, a big quake that caused little damage is like a fairy-tale dragon showing itself without spewing fire, giving villagers a chance to assess its dangers.

This is a dragon that has scientists enthralled. Katherine Kendrick is one of three geologists who helicoptered in on the night of the quake and found the rupture. “This is amazing,” she recalled repeating to herself continually.

Michael Forrest, a fault specialist with the Southern California Earthquake Center, grinned for two hours straight Monday as he hurried along the fault, swooping down for a closer look at the cracks.

“It feels like swimming; you know, where you feel weightless and giddy,” he said. “I want to follow the fault; look at it; stare at it for hours. It sort of feels like being in love.”

Perhaps the only earth scientist who remained unfazed was geology legend Tom Dibblee, the first to map the 650-mile-long San Andreas fault.

In the early 1960s, Dibblee spent months alone in this part of the Mojave mapping faults where lava flows were interrupted by earthquakes that took place 30,000 years ago. He took note of the fantastic rock shapes and other geological landmarks of the area.

But 88-year-old Dibblee dismissed Saturday’s quake as an item of passing interest.

“To me, earthquakes are incidental, just a matter of natural phenomenon,” said the Santa Barbara resident. “No earthquake in California has ever been predicted.”

Not that Dibblee is completely immune to the fault’s thrill. He has mapped the geology of more than 40,000 square miles of California and is eager to add a new active fault to his portfolio.

“I can’t wait to see this new one on a map,” he said. “Now that will be exciting.”