The Fabled Island of California? Stunning New Research Suggests the Early European Explorers may have been Right

Source: https://en.wikipedia.org/wiki/Island_of_California

Some of the earliest maps of California show it to be an island. The "correction" to this misconception didn't occur until 1746 when the Gulf of California and its terminus at the delta of the Colorado River were accurately mapped. For something like two hundred years, the legend persisted that California was a giant island, populated by beautiful women, and possessing vast treasures.

Geologists, geographers, and cartographers have long wondered about this conundrum. How could so many explorers have made such a huge error? Some stunning new research reveals that the explorers may have been right all along. In a paper published in the journal Enquiries (the national edition), geologists have come up with a startling model that suggests that as recently as 250 years ago, California was an island.

Seismologists have long known that most earthquakes are the result of elastic rebound, a theory that suggests that earthquakes occur because of a build-up of stress along faults. Frictional resistance prevents the fault from moving while stresses accumulate, but at some point the stresses overcome the resistance and the fault moves, generating large earthquakes. The idea was proposed by Professor Harry Fielding Reid after the Great San Francisco Earthquake of 1906, and evidence derived from subsequent earthquakes has confirmed the model.

Professor Avril Primum was the lead researcher. She says that the work of her team along the San Andreas fault in Southern California has provided a crucial addition to the model of elastic rebound. Sometime around 1250 AD, a huge earthquake caused massive slip along the fault and a vast region separated from the edge of the continent. But unlike models that would have left California as a permanent island, Primum's team argues that the elastic nature of the upper crust actually caused the island to rebound back to the edge of the continent, maybe during an epic earthquake reported in the early 1700s.

Avril contends that we don't have to worry so much about California falling into the sea. Sure, it might do it, and Duane Johnson, Pierce Brosnan, and Tommy Lee Jones will have to run around saving stranded people, but ultimately the elastic forces will pull it right back just like a bungee cord. We just need to be patient.

California is Going to Fall into the Sea! Quiz Question #1

Comic art courtesy of Zeo

Thursday, while preparing for my public lecture on earthquakes and California, I blogged a short true-false quiz that I was going to present to my audience. We had a great time on Friday night, I think. 300 community members came out on a Friday night to see a science lecture! Anyway, here was the first of the questions:

California is going to fall into the sea: true or false?

This is one of those persistent statements about California earthquakes that everyone "knows", even if they live in New Jersey. I had a pretty savvy audience; they had a better than average understanding of earthquakes, and answered with the obvious answer: false.

I then offered up the correct answer:

True!

In fact, not only is it going to happen, it already has.

Check out the NASA photo above. When we speak of California, we often forget that most people are only thinking of one part of California: Alta California (upper California). The image above reminds us that Baja ("Lower") California is also part of our geography. And Baja has already fallen into the Pacific Ocean, in a reasonable interpretation of the statement. Baja was once connected to the Mexican mainland, and has been a peninsula for only the last four million years or so. It is the beginning of a massive rift that will ultimately tear Alta California apart, and send it traveling northwest at all of two inches a year. The two inches per year will actually be taken up by large earthquakes shifting the landscape 10-15 feet every century or so.

In 20 million years, the Dodgers and Giants will again be crosstown rivals (yes, I stole this joke from the DVD "Planet Earth"). In 70 million years, California may slam into the south margin of Alaska, pushing up another high mountain range.

Want to see how this happened? Tanya Atwater of UCSB, the plate tectonics pioneer who figured out the origin of the San Andreas fault, has a series of excellent animations available for download at this site. If you have a fast connection, try this one (50 mb).

Courtesy of Tanya Atwater. See the animation here.

If you have a slower connection, this animation is 20 mb. Both animations show the complex interactions of the continental margin, with some parts being rotated, and others moving northwest along the San Andreas. And Baja California opening up to form a new seaway, the Gulf of California.

So indeed, it could be a good idea to buy up some property in the western Mojave Desert to be ready for your oceanfront views...in ten million years...if you want to wait that long.

What? You thought the question was about California falling into the sea during one earthquake? Really? Like the movie 2012? Not gonna happen. That's tabloid stuff. Aliens kidnapped me last week too.