Effect of the 1906 Eathquake along the Mendocino Coast

As I tell visitors yo our layout the San Andreas fault is just four miles offshore. The 1906 Earthquake hit all the towns along the California coast north of San Francisco to north of Eureka.

This piece that appeared in the local newspaper tells the story of the earthquake.

 

Effect of 1906 Earthquake along the Mendocino Coast

This picture shows shops on Fort Bragg Main Street after the quake.

Fort Bragg Main Street after the 1906 earthquake – building on left is now Racines

July 2019 7.1 earthquake centred on Ridgecrest in Southern California

I’m a natural events freak. I admit it. Ever since the 7.i I have been reading about it.

The Ridgecrest earthquakes of July 4 and 5 occurred north and northeast of the town of Ridgecrest, California and west of Searles Valley, California (approximately 122 miles north-northeast of Los Angeles). There were three main shocks of magnitudes 6.4, 5.4, and 7.1, and many perceptible aftershocks, mainly within the area of the Naval Air Weapons Station China Lake. The first main shock (now deemed to be a foreshock) occurred on July 4 at 10:33 a.m. PDT, approximately 11.2 miles ENE of Ridgecrest, and 8.1 mi WSW of Trona, on a previously unnoticed NE-SW trending fault where it intersects the NW-SE trending Little Lake Fault Zone.

This quake was preceded by several smaller earthquakes, and was followed by more than 1,400 detected aftershocks. The M 5.4 and M 7.1 quakes struck on July 5 at 4:08 a.m. and 8:19 p.m. PDT approximately 6 miles to the northwest. The latter, now considered the mainshock, was the most powerful earthquake to occur in the state in 20 years. Subsequent aftershocks extended approximately 30 miles along the Little Lake Fault Zone. Relatively minor damage resulted from the initial foreshock, though some building fires were reported in Ridgecrest near the epicenter. The main quake on July 5 cut power to at least 3,000 residents in Ridgecrest. Effects were felt across much of Southern California, parts of Arizona and Nevada, as far north as the San Francisco Bay Area and Sacramento, and as far south as Baja California, Mexico. An estimated 20 million people experienced the foreshock, and approximately 30 million people experienced the main shock. We didn’t feel it here in Fort Bragg in Northern California.

Click on the images to see full size.

Here’s a map showing where this earthquake and other southern California earthquakes were located:

Location of Ridgecrest Earhquake

Location of Ridgecrest Earthquake

What areas were affected:

Potential disaster area of the Ridgecrest earthquake

Potential disaster area of the Ridgecrest earthquake

These two ground level pics show the damage caused by the quake:

Crack in the earth opened up by the Ridgecrest quake

Crack in the earth opened up by the Ridgecrest quake

Road damage caused by the Ridgecrest quake

Road damage caused by the Ridgecrest quake

This aerial pic REALLY shows the severity of the quake. The road has been displaced several feet:

Road displaced by the Ridgecrest quake

Road displaced by the Ridgecrest quake

This before and after pic I got from Google Maps. You need to click on the pic to see the animated effect.

Before and after animation of the Ridgecrest quake

Before and after animation of the Ridgecrest quake

 

 

 

 

 

Earthquakes felt along the Mendocino Coast

Two Saturdays ago I was sitting at my desk when my chair moved, my fob watch swung on its’ chain and a picture on the wall gyrated. Earthquake!! I looked up the USGS site and found that it was a 5,6 quake centred near Fortuna which is to the north of us who live in Fort Bragg.  It was a magnitude 5.6 earthquake and was reported at 8:53 p.m. on California’s North Coast. The quake was felt to the north in Eureka and also to the south. There were no reports of damage or injuries and there was no tsunami. The map below shows just how much seismic activity there is in the Fortuna area.

Earthquake activity ariund Fortuna

Earthquake activity around Fortuna

And this map shows just how much seismic activity there is in Northern California on an ongoing basis:

Eathquake Activity in Northern California and Nevada

Eathquake Activity in Northern California and Nevada

Me being an auditor sat there wondering just how much, how bad, how many big ones there have been along the Mendocino Coast. I remembered that Thad Van Buren’s book, “Belonging to Places” had a table in it showing earthquake events over a long period of time:

Earthquake Events

Earthquake Events

We are on the coast so my next question was, “And Tsunamis?” Again Thad Van Buren came to the rescue with this table:

Tsunami Events Table

Tsunami Events Table

Having absorbed that I DEFINITELY decided that I was better off here vs the East Coast – Hurricanes, or middle America – Tornadoes.

 

Point Arena Lighthouse

The lighthouse at this site was constructed in 1870. The brick-and-mortar tower included ornate iron balcony supports and a large keeper residence with enough space to house several families. The April 1906 earthquake struck the light station. The keeper’s residence and lighthouse were damaged so severely they had to be demolished. The United States Lighthouse Service contracted with a San Francisco based company to build a new lighthouse on the site, and specified that it had to be able to withstand any future earthquakes. The company chosen normally built factory smokestacks, which accounts for the final design for the new Point Arena Lighthouse, featuring steel reinforcement rods encased in concrete. This was the first lighthouse built this way.

The new lighthouse began operation in 1908, nearly 18 months after the quake. It stands 115 feet tall, and featured a 1st Order Fresnel Lens, over six feet in diameter and weighing more than six tons. The lens was made up of 666 hand-ground glass prisms all focused toward three sets of double bullseyes. It was these bullseyes that gave the Point Arena Lighthouse its unique “light signature” of two flashes every six seconds. The optics, which held an appraised value of over $3.5 million, was set in solid brass framework, and was built in France.

Prior to the introduction of electricity, the lens was rotated by a clockwork mechanism. The Keepers, or “wickies” as they were called, had to hand crank a 160-pound weight up the center shaft of the lighthouse every 75 minutes to keep the lens turning. Light was produced by a “Funck” hydraulic oil lamp, that needed to be refueled every four hours, and whose wicks would have to be trimmed regularly. Later, two 1,000 watt electric lamps were installed to replace the oil lamp, and a ​18 horsepower electric motor was installed to replace the clockworks.

Below are three recent photos of the Point Arena Lighthouse.

Point Arena Lighthouse

Point Arena Lighthouse

Point Arena Lighthouse at night

Point Arena Lighthouse at night

Point Arena Lighthouse in the moonlight

Point Arena Lighthouse in the moonlight

1906 Earthquake -Surface Evidence

An intriguing question was posed to me today by a visitor who was EXTREMELY surprised to learn that Fort Bragg along with every other town along the Mendocino Coast was severely damaged in the 1906 earthquake. The question was, “Was there any evidence of the earthquake that a person could see absent the damage to structures?”

I told the man about the Earthquake Trail at Point Reyes National Park – he hadn’t heard of it. I also told him that I had one, maybe two pics of the fault rupture on the surface. I told him I would post the pics here if I had them. Well. I do have them and here they are:

A split on the north end of East Street from the earthquake. East St. is now the Embarcadero. San Francisco, California: 1906.

A split on the north end of East Street from the earthquake. East St. is now the Embarcadero. San Francisco, California: 1906.

1906 earthquake rupture at ground level

1906 earthquake rupture at ground level

Also in my file were two clips about the 1906 earthquake that were contained in out of state newspapers:

Cincinnati Post April 19th 1906

Cincinnati Post April 19th 1906

Portland Evening Telegram of April 19th 1906

Portland Evening Telegram of April 19th 1906

The headlines pretty well tell the story.

California Megaflood of 1861-62

I was trying to find out when the State of California and Fort Bragg received the greatest rainfall. I am still totally freaked out by what I found ……..

“Geologic evidence shows that truly massive floods, caused by rainfall alone, have occurred in California every 100 to 200 years. Such floods are likely caused by atmospheric rivers: narrow bands of water vapor about a mile above the ocean that extend for thousands of miles.  The only megaflood to strike the American West in recent history occurred during the winter of 1861-62. California bore the brunt of the damage. This disaster turned enormous regions of the state into inland seas for months, and took thousands of human lives. The costs were devastating: one quarter of California’s economy was destroyed, forcing the state into bankruptcy.

Today, the same regions that were submerged in 1861-62 are home to California’s fastest-growing cities. Although this flood is all but forgotten, important lessons from this catastrophe can be learned. Much of the insight can be gleaned from harrowing accounts in diary entries, letters and newspaper articles.

In 1861, farmers and ranchers were praying for rain after two exceptionally dry decades. In December their prayers were answered with a vengeance, as a series of monstrous Pacific storms slammed—one after another—into the West coast of North America, from Mexico to Canada. The storms produced the most violent flooding residents had ever seen, before or since. Sixty-six inches of rain fell in Los Angeles that year, more than four times the normal annual amount, causing rivers to surge over their banks, spreading muddy water for miles across the arid landscape. Large brown lakes formed on the normally dry plains between Los Angeles and the Pacific Ocean, even covering vast areas of the Mojave Desert. In and around Anaheim,  flooding of the Santa Ana River created an inland sea four feet deep, stretching up to four miles from the river and lasting four weeks.

Residents in northern California, where most of the state’s 500,000 people lived, were contending with devastation and suffering of their own. In early December, the Sierra Nevada experienced a series of cold arctic storms that dumped 10 to 15 feet of snow, and these were soon followed by warm atmospheric rivers storms. The series of warm storms swelled the rivers in the Sierra Nevada range so that they became raging torrents, sweeping away entire communities and mining settlements in the foothills—California’s famous “Gold Country.” A January 15, 1862, report from the Nelson Point Correspondence described the scene: “On Friday last, we were visited by the most destructive and devastating flood that has ever been the lot of ‘white’ men to see in this part of the country. Feather River reached the height of 9 feet more than was ever known by the ‘oldest inhabitant,’ carrying away bridges, camps, stores, saloon, restaurant, and much real-estate.” Drowning deaths occurred every day on the Feather, Yuba and American rivers. In one tragic account, an entire settlement of Chinese miners was drowned by floods on the Yuba River.

This enormous pulse of water from the rain flowed down the slopes and across the landscape, overwhelming streams and rivers, creating a huge inland sea in California’s enormous Central Valley—a region at least 300 miles long and 20 miles wide. Water covered farmlands and towns, drowning people, horses and cattle, and washing away houses, buildings, barns, fences and bridges. The water reached depths up to 30 feet, completely submerging telegraph poles that had just been installed between San Francisco and New York, causing transportation and communications to completely break down over much of the state for a month. One-quarter of the state’s estimated 800,000 cattle drowned in the flood, marking the beginning of the end of the cattle-based ranchero society in California. One-third of the state’s property was destroyed, and one home in eight was destroyed completely or carried away by the floodwaters.

Sacramento, 100 miles up the Sacramento River from San Francisco, was (and still is) precariously located at the confluence of the Sacramento and American rivers. In 1861, the city was in many ways a hub: the young state’s sparkling new capital, an important commercial and agricultural center, and the terminus for stagecoaches, wagon trains, the pony express and riverboats from San Francisco. Although floods in Sacramento were not unknown to the residents, nothing could have prepared them for the series of deluges and massive flooding that engulfed the city that winter. The levees built to protect Sacramento from catastrophic floods crumbled under the force of the rising waters of the American River. In early January the floodwaters submerged the entire city under 10 feet of brown, debris-laden water. The water was so deep and dirty that no one dared to move about the city except by boat. The floodwaters caused immense destruction of property and loss of life.

California’s new Governor, Leland Stanford, was to be inaugurated on January 10, but the floodwaters swept through Sacramento that day, submerging the city. Citizens fled by any means possible, yet the inauguration ceremony took place at the capital building anyway, despite the mounting catastrophe. Governor Stanford was forced to travel from his mansion to the capital building by rowboat. Following the expedited ceremony, with floodwaters rising at a rate of one foot per hour, Stanford rowed back to his mansion, where he was forced to steer his boat to a second story window in order to enter his home. Conditions did not improve in the following weeks. California’s legislature, unable to function in the submerged city, finally gave up and moved to San Francisco on January 22, to wait out the floods. Sacramento remained underwater for months.

Downstream of Sacramento, towns and villages throughout the eastern San Francisco Bay Area were struggling with catastrophes of their own. Twenty miles northeast of San Francisco, four feet of water covered the entire town of Napa; to the east, the small town of Rio Vista on the Sacramento River was under six feet of water. The entire population of Alamo, at the foot of Mt. Diablo 50 miles east of San Francisco, was forced to flee rising floodwaters. People abandoned their homes in the middle of the night. Some found refuge, others drowned. The San Ramon Valley was one sheet of water from hill to hill as far as the eye could see. The destructive force of the floods was awesome: houses, otherwise intact and complete with their contents, were carried away in the rapids; horses, cattle, and barns were swept downstream for miles.

The heavy rains also triggered landslides and mud slides on California’s steep hillsides. For instance, in Knights Ferry and Mokelumne Hill, nearly every building was torn from its foundation and carried off by thundering landslides, and a major landslide also occurred at the town of Volcano in the Sierra foothills, killing seven people.

Why so many people were caught off-guard by these floods remains a mystery, but clearly these immigrants did not recognize the climatic warning signs. They had never experienced such extreme flooding in the 12 years since the Gold Rush began, although lesser floods were not uncommon. It appears that the Native American populations, who had lived in the region for thousands of years, had deeper insights to the weather and hydrology, and recognized the patterns that result in devastating floods. A piece in the Nevada City Democrat described the Native American response on January 11, 1862:

We are informed that the Indians living in the vicinity of Marysville left their abodes a week or more ago for the foothills predicting an unprecedented overflow. They told the whites that the water would be higher than it has been for thirty years, and pointed high up on the trees and houses where it would come. The valley Indians have traditions that the water occasionally rises 15 or 20 feet higher than it has been at any time since the country was settled by whites, and as they live in the open air and watch closely all the weather indications, it is not improbable that they may have better means than the whites of anticipating a great storm.'”

The text above was cobbled together from a number of sources. Along the way I found some interesting pics and visuals. This map shows the extent of the flood:

Map of 1861-62 Flood area

Map of 1861-62 Flood area

These three (poor quality) pics show the reporting of the time:

Hypothetical Simulation of a Ark Storm

Hypothetical Simulation of a Ark Storm

As I read it it’s not a question of whether it will happen again but when. Global warming anyone???????

Severity of 1906 Earthquake in Fort Bragg, CA

Fort Bragg is, give of take, 170 miles from San Francisco.

When you enter the door of our layout in Fort Bragg there is a leaning lighthouse and a poster explaining that the Point Arena was toppled in the 1906 earthquake. There is another poster adjacent to the Jug Handle Creek diorama showing the huge trestle that spanned the Jug Handle Creek before and after the earthquake. The Jug Handle Creek trestle was completely destroyed in the earthquake.

Notwithstanding the pictorial evidence I am frequently asked if the 1906 was felt in Fort Bragg. Visitors seem surprised to learn that not only was it felt in Fort Bragg it was felt along the entire Mendocino Coast. An oft repeated comment is “Wow, I didn’t know that.” To see photos of some of the damage along the Mendocino Coast, click here.

Heretofore I have been unable to find easily explainable pictorial evidence of the severity of the earthquake north of San Francisco. Well, that may have changed. Thanks to Lynn Catlett’s “You know you’re from Mendocino if ….. ” Facebook page I have obtained the chart depicted below: (Please click to enlarge)

Chart showing severity of the 1906 earthquake north of San Francisco

Chart showing severity of the 1906 earthquake north of San Francisco

The black line is the San Andreas fault. As you can see the quake was felt very widely. If my reading of the colour coding is correct Fort Bragg is in the moderate to heavy area of damage. Proof?

 

How bad was the 1906 earthquake up and down the Mendocino Coast?

This is a question we frequently get asked by visitors. Many think the quake damage was limited to the Bay Area and are astonished to learn that the answer was .very bad. Check out our web page  and see just how bad. Two  “new” pics have come to my attention which emphasise the severity of the quake locally. We’ll add these to those on the web page.

Fort Bargg Bank of America Building

I believe this was on the narrow gauge line that ran to Duncan Mills

886219_439370739585838_7040094425939878387_oThis is the remains of the Bank of America which at the quake was on the west side of Main Street. Today it is offices.