Learning to Appreciate Earthquakes

The 5.1-magnitude La Habra earthquake on March 29 demonstrated the typical average-sized temblor Southern Californians should be accustomed to.
| Photo: U.S. Geological Survey

Things got a little shaky around here last month.

Many in the Los Angeles area were awakened with a top o' the morning 4.1-magnitude "Shamrock Shake" on March 17, which was centered in the Santa Monica Mountains above Encino. Just 12 days later, on the evening of March 29, a series of tremors centered in La Habra that began with a 3.6 foreshock and peaked with a 5.1 quake that was felt around much of Southern California added to the seismic show beneath our feet. It was the biggest earthquake to rattle the Southland in six years.

Whenever these things happen, it invariably becomes a numbers game, with magnitudes reported on traditional and social media to keep everything in perspective as we anticipate the dreaded "Big One."

We humans fear what we cannot really understand. So maybe it's time for us Southern Californians to understand earthquakes a bit more. Or maybe even appreciate them.

Like snakes and sharks, earthquakes are seemingly menacing things that we tend to fear due to the perceived danger they can bring. But like snakes and sharks, the vast majority of them are rather harmless -- Southern California experiences some 10,000 earthquakes annually, though only a few hundred of them measure above 3.0 in magnitude.

Perhaps the most unsettling thing about earthquakes is that they challenge our incorrect notion that the ground is solid.

The theory of plate tectonics, the most widely-accepted scientific explanation for the formation of our planet's landmasses and oceans, suggests the ground is in fact not a solid object, but something that is in a constant state of change, albeit one that cannot be as easily detected by the relatively short span of human recorded history, much less within the relatively short lifespans of humans themselves. In author John McPhee's 1993 book, "Assembling California," where he tags along with geologists who show him how much of the geophysical profile of the Golden State was formed, he wrote, "Fifty thousand major quakes will move something about a hundred miles. After there was nothing, earthquakes brought things from far parts of the world to fashion California." -- The latter sentence also being an interesting parallel to our state's human composition.

But I've always thought of the notion of "Earthquake Country" as somewhat silly, as well as inaccurate, given the context of the East Coast vs. West Coast dichotomy many Americans subscribe to. It's as if it suggests that earthquakes are the price Californians pay for, say, our favorable year-round climate (On the contrary, the most seismically-active state is not California, but Alaska, and the most damaging earthquake to hit the U.S. this century was actually centered in Virginia). The notion of "Earthquake Country" is silly given that some two-thirds of the world's population lives in a seismically-active zone, making a large part of the planet -- as opposed to a single region -- "Earthquake Country."

But if earthquakes are the price we pay, then so be it. The very mountains that we ski on, hike in, or drive up to in order to enjoy spectacular views of the landscape below, are all there because of earthquakes. The peaks and ranges that are home to icons such as the Hollywood Sign, Big Bear Lake, and the Griffith, Mt. Wilson, and Palomar observatories, are all built up by temblors. The very hills that define the character of our communities, and are embedded in their names, be they Woodland, Rolling, Baldwin, Anaheim, Puente, or Beverly, were all created by seismic movements. The 5.1 quake that was centered in La Habra in late March likely lifted the Puente Hills by a few centimeters. To human eyes, the profile of the hills look much the same as they always have been, but in millions of years, they will likely be towering, unrecognizable peaks. Elsewhere, quakes have gradually created the Alps, the Himalayas, the Andes. Without earthquakes, the world would be -- quite literally -- flat.

Dare I say that we are "fortunate" to have earthquakes. A hurricane or typhoon unleashes its destruction over several hours. An earthquake, even the most damaging ones, will last but seconds, minutes at the most. In a hurricane, your house will likely flood. Your carpets and walls will be inundated with water, and when the flood waters cease, mold will take over. In an earthquake, anything that wasn't damaged following the quake likely stays undamaged (as long as you shut the gas off after you've smelled it).

Even the types of earthquakes in Southern California we can be somewhat thankful for. Unlike Japan, Indonesia, Alaska, or Chile, we do not live near a subduction zone, where one of the earth's tectonic plates slams under another. Those conditions create the enormous magnitude 9-and-above quakes that not only cause unprecedented shaking, but the equally disastrous tsunamis that can bring about destruction in faraway lands. A magnitude 8 earthquake, however powerful it can be, is the worst that can happen around here (Seattle and the rest of the Pacific Northwest, have an even bigger "Big One" on their hands).

The Tongva (a.k.a. Gabrieleño) people, the native American tribe that has lived for thousands of years in what is now the Los Angeles area, lived with earthquakes (which they called "yaaytok"). Their folklore explained that the world was built on the backs of seven large turtles (how similar to plate tectonics that is), that moved when angered, causing temblors. Of course, the Tongvan built environment consisted of dwellings made out of whale bones, reeds, and grasses -- earthquakes were no more catastrophic than the wind and the rain. It was only after Spanish settlement and colonization, with the introduction of structures made of stone and masonry, that quakes became dangerous phenomena.

Of course, it's unrealistic to expect 21st century Southern Californians to go back to living in small grass huts, but the most we can do is continue to improve earthquake-resistant designs. The older quake-vulnerable structures will either go away or be reinforced, in a form of structural darwinism: Only the most quake-resistant buildings will survive in the long run.

Appreciating earthquakes does not mean we morbidly revel in casualties, of course. Deaths and injuries are inevitable consequences of any major quake. But the onus is on human societies to minimize them as much as possible. We must always be prepared for earthquakes -- both during the event and the potential aftermath. We can train ourselves through earthquake drills. We can invest in warning systems than can detect and alert us of seismic waves before they reach the surface. We can educate ourselves on seismic activity to dispel popular myths about quakes, such as "earthquake weather" or the notion of "California falling into the sea."

But we just can't prevent earthquakes themselves. They have happened on this planet before there were humans, and will continue to happen after we're long extinct.

Each year, earthquakes typically claim the lives of 10,000 people worldwide. But in comparison, car accidents claim 1.2 million lives worldwide (including over 30,000 in the U.S. alone) annually. So your risk of succumbing to a quake, or any other natural disaster, is much, much smaller than the human-generated activity of our daily lives.

Most likely the next earthquake you will feel will be a small or moderate one, which will more likely cause a flurry of tweets on Twitter than any significant damage or human harm. So take a moment to appreciate the power of our active planet that you were able to bear witness to.

About the Author

Elson Trinidad is the Managing Editor of KCET's 50th Anniversary website and writes the "Transpacific Routes" and "Concrete and Chaparral" columns on KCET's blogs.
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