The initial 7.2 quake on April 25, late on a spring Saturday morning, happened at the very southern edge of the Northwest seismic zone, where the Gorda Plate meets the North American Plate and the San Andreas Fault goes out to sea: the Pacific Plate edging up against the two other plates makes it a triple junction known as the Mendocino Fault Zone. Early the next morning, a magnitude 6.5 earthquake hit the same area, and then a 6.7 quake hit a few hours later; a series of relatively small aftershocks followed in the ensuring days. The USGS describes the series as the Cape Mendocino earthquakes. This is from the Sacramento Bee of April 26:
In Ferndale, the 140-year-old town was celebrating its first Best of the West festival when the quake hit, crumbling the brick facades of buildings and panicking hundreds who were watching a parade along Main Street.
Police estimated 80 percent of the downtown buildings in the town of about 1,400 were damaged, along with 15 homes knocked off their foundations.
“We’re used to these, but this one was worse than any I’ve seen before,” said Marlin Mesman, owner of the Golden Gait mercantile store. “They were going up the front door and one woman fell down, and another stepped right on her back and kept going because it was ‘Panic City.’”
In Rio Dell, a town of about 3,750, more than two-thirds of the window fronts along the main street were shattered.
Jim and Cindy Rich had just opened their restaurant, the Pizza Factory, when the quake hit. It destroyed a 55-gallon aquarium, broke the legs on a 5,000-pound refrigerator and knocked Jim Rich down.
“I never had one knock me down before,” Rich said. “I’m a native Californian and have been in quakes before. That scared me. I thought I was in the big one.”
The quake was arbitrary in its infliction of damage. While much of downtown Rio Dell was trashed, there was little apparent damage in Scotia, a town of about 1,200 just across the Eel River. Stacks of lumber at the huge Scotia mill remained undisturbed.
In Ferndale, the quake shook up the first Best of the West Day, which was meant to celebrate the town’s claim to being the town farthest west in the lower 48 states.
About 300 people had lined the street for a horse parade that was ending as the quake hit, and dozens of others were poking through antique shops and bookstores in the 100 year old buildings that line the main thoroughfare.
“They were ashen-faced and just scared to death,” said store owner Marlin Mesman. One woman said, “That’s the most horrifying thing I’ve ever seen.”
Richard DeGroot, a 45 year old Seattle businessman, was in town to visit his sister before she underwent cancer surgery. He and his family were sitting at table in the Palace Bar when things started to shake.
“Some guy shouted, ‘Get out into the street!’” he said from a hospital bed in Fortuna. “I headed out, and I thought everybody was right behind me. Thank goodness they weren’t.”
DeGroot was hit by hundreds of bricks from the building’s facade as he fled through the door, badly breaking one leg and both feet.
“If I had been two feet back,” he said, “I wouldn’t be here now.”
The age of many of Ferndale’s buildings may have saved them.
Many residents said they don’t carry earthquake insurance because the area’s frequent quakes make premiums too expensive. But Frank Shunk wishes he had.
Shunk’s 100 year old Victorian home, which he had just finished remodeling, was flung nearly 15 feet toward the street and eight feet to one side. His stepson, Daniel, 15, was on the second floor playing a video game when the temblor struck. When the planks in the wooden flooring snapped upward and pinned the front door shut, Daniel was forced to leap to the sidewalk.
“He jumped out the window,” said Matt McKenzie, Daniel’s 17 year old brother. “But it used to be 10 feet higher.”
The jolt knocked both units of PG&E’s Humboldt Bay fossil-fuel plant off-line, although it was being brought back on line Saturday evening. Utility officials said there was no damage to the mothballed nuclear plant nearby.
The initial, 7.2 quake set a fire caused by a broken gas main, which destroyed much of the business district of Scotia. A firefighter said: “This is our town right here and now it’s gone.”
On Monday, the 27th, the San Jose Mercury News told the story of the ongoing toll of the quakes:
The terror of aftershocks has faded to fatigue as shaken residents of the Lost Coast region warily tackle cleanup efforts in the wake of a major earthquake and powerful aftershocks.
”If I knew there wasn’t going to be another earthquake, I would work my butt off and clean everything up. But you don’t know,” said Scotia Inn owner Hillori Carley.
The aftershocks Sunday came like a one-two punch on top of Saturday’s 6.9 temblor.
The quakes touched off fires that burned down the center of Scotia, and knocked out power and phone service to areas of Humboldt County. State officials said National Guard units trucked in drinking water to the four towns hardest hit by the quakes.
The initial strong shock — which snapped water mains and hampered firefighting efforts — was followed at 4:18 a.m. by a magnitude 6.5 quake that rattled homes as far south as Aptos and Fresno, capping a tumultuous weekend in this picturesque coastal community where timber is king.
Damage from the quakes was estimated at $47 million — $27 million to homes and businesses, and $20 million to roads and bridges, according to Humboldt County Sheriff David A. Renner.
Local hospitals treated 94 people for injuries over the weekend, among them four firefighters suffering from smoke inhalation. Twelve people were admitted. There were no reports of deaths.
Rio Dell building inspector Marc Phippen estimated 25 homes and 10 businesses in the town of 3,000 are uninhabitable. At the Rio Dell Bowl, assistant manager Rita Ruff kept her sense of humor about the damaged bowling alley, saying, “They wanted a face lift, but this wasn’t the way to do it.”
”People are fatigued,” said Stan Dixon, chairman of the Humboldt County Board of Supervisors. “They’re beginning to realize the extent of the damage. We’ve got some mental health counselors for people who need it. It’s beginning to sink in now, and a lot of people are beginning to hurt.”
Residents were prepared for aftershocks from Saturday’s 6.9 earthquake, but few were ready for the ferocity of the early morning jolts that left people sleepless, edgy and worried the worst was not over.
In Petrolia, the post office and several other buildings burned to the ground, and a number of houses were damaged.
In Ferndale, a town of Victorian-style buildings 10 miles northwest of Scotia, residents said the pre-dawn aftershocks seemed to move up and down, rather than side to side like the motion of Saturday’s tremor.
”It was like someone picked up my house, pushed it forward and dropped it,” said Danielle Gyurik, 29, whose bed-and- breakfast is located in the town’s third-oldest house.
Artist Hobart Brown returned home Sunday to find about $50,000 in damage to the metal sculptures he makes and the other art he sells at his gallery in downtown Ferndale.
The quakes frightened some people so much they stayed out of their houses Sunday night. “You know there are some 3’s and 4’s (on the Richter scale) coming,” said Sandra Messman. “That’s why no one is going into the buildings.” Messman slept in a camper parked outside her store. Other people set up tents in their front yards.
It was much the same in Fortuna.
”I’ve lived here all my life and been through the floods, but I ain’t seen nothing like this,” said Lisa Tarelli, as she swept up the glass at a Fortuna grocery after the first big aftershock.
”Everything we had picked up Saturday was back on the floor today,” said Sondra Kirtley, whose family has operated an auto parts store in Fortuna for 24 years. “The first earthquake seemed to really kind of roll. But (Sunday’s first) quake was more of a sharp jolt. Everybody’s tired. Everybody’s weary. I don’t think a lot of people got a lot of sleep last night.”
At the same time, the San Francisco Chronicle noted that that “over a frightening weekend only last August [of 1991], several sharp quakes jolted the area. One hit just south of Cape Mendocino with a magnitude of 6, while others on the Gorda Plate offshore from Eureka registered magnitudes as high as 6.9.”
Just a few months earlier, at the start of 1992, David Perlman of the Chronicle had noted the threat of a much stronger earthquake off the coast:
Geologists probing the restless earth along the Humboldt County coast near Eureka have discovered the strongest evidence yet that truly monstrous earthquakes have rocked the Northwest in the past — and could strike again.
In the Northwest off the Pacific Coast, a large segment of Earth’s crust called the Gorda Plate and an even larger one called the Juan de Fuca Plate are thrusting themselves beneath the North American continent in an inexorable process called subduction. The entire region, stretching northward from the so-called “Mendocino Triple Junction” where the San Andreas Fault swings westward into the Pacific, is known as the Cascadia subduction zone.
As the massive crustal plates of the zone grind their way downward under the western margin of the continental plate tens of miles offshore, they push eastward beneath the land as well. The moving slabs may slide imperceptibly for hundreds of years, then lock tight for a period while strain builds up, and then jolt suddenly into motion again.
Similar processes are at work in many regions of the world — off Japan, Alaska and the coast of South America. They generate deadly volcanic eruptions and raise up mountains as high as the Andes over millions of years.