Saturday, September 12, 2015

Vagabonding on Dangerous Ground: Danger Follows Us Home (As it does all of us)

Mt. St. Helens from Silver Lake
We have finally reached the last few days of our meandering journey through the lands influenced by the Cascadia Subduction Zone. We spent several weeks out there, checking out the landscapes threatened by a possible magnitude nine earthquake. Although the hazard has been recognized for quite a few years, there was a media storm over the summer that brought the dangers into focus for the people living in the coastal zones of the Pacific Northwest. We were on our vacation anyway, traveling up the coast, but our search for beautiful scenery became an exploration of geological landscapes threatened by earthquakes, landslides, tsunamis and floods.
After many days in Oregon, Washington and British Columbia, we were on the homeward road, traveling hundreds of miles a day, knowing that issues at home needed attention. It didn't leave much time to investigate the other danger facing those in the northwest: volcanic activity. We got to see Mt. Baker for the first time, and Mt. Garibaldi, but Mt. Rainier and Mt. St. Helens were hidden in the clouds (we had a brief view of St. Helens from Silver Lake; see the first picture). Mt. Hood, the Three Sisters, Crater Lake, and all the other Cascade volcanoes were hidden behind the forested ridges. We couldn't see them from the freeway, and we had no time for detours.
But then we crossed back into California, forded the Klamath River, and surmounted a ridge where a gigantic mountain came into view. It was Mt. Shasta (14,179 feet / 4,322 meters), one of the southernmost volcanoes in the Cascade Range (Lassen Peak is down that way too). Although it is a few hundred feet shorter than Mt. Rainier, it has much more volume. Not only is it the largest volcano in the Cascades, it is the second most active, exceeded in that department only by Mt. St. Helens. Eruptive activity occurs every 600 years or so. The last eruption was an ash explosion 200-300 years ago, possibly witnessed in 1786 (this is disputed; wildfires can look much like volcanic eruptions).

Like any active volcano, Shasta is dangerous. It's not just lava flows (that Hollywood staple), but potential ash flows, and volcanic mudflows (lahars), made all the more likely by the presence of California's largest glaciers around the summit. Many times the lahars occur without eruptive activity (at least 70 times in the last 1,000 years) as glaciers melt in the warmer seasons. Most of the towns near Shasta are built atop lahar deposits (around 10,000 people live in the immediate vicinity of the volcano). 

The pictures in this post are unique in one sense; they were mostly taken from a moving vehicle (by Mrs. Geotripper; I was trying to concentrate on driving). We had come 250 miles already, and had another 250 before we would get home, so we just didn't have time to linger. Driving does give one time to think, though, and I was thinking about the nature of geologic hazards.

We had just spent weeks traveling through a region that could potentially be devastated by an entire buffet of disasters. And yet millions of people live there, either unaware or willing to take the chance in order to enjoy the amenities of living in a coastal paradise, or someplace incredibly green and scenic. I felt no sense of relief from getting out of that danger zone because I understood that any one of those disasters had a very small chance of taking place while I was there. Even if something had happened, we were stocked up and prepared to be on our own for upwards of a week or more. But the clock was ticking, and the longer one stays, the greater likelihood that something bad will happen.

But a geologist's perspective provides little comfort. Going home to familiar ground was no protection from geologic disaster, whether sudden or over decades. I live in a flat and (dare I say it?) boring place, and yet I face geologic disasters every day. I live only about fifty miles from the San Andreas fault, and just twenty or thirty miles from lesser-known but active faults. I live next to a major river that is prone to flooding every few years. My town is just eighty miles or so from a rhyolite caldera that is more active than the "supervolcanoes" of Yellowstone National Park. And for the last four years we have been suffering through an unprecedented drought unlike any ever faced by modern-day California (although precedents exist in the recent geologic past). There's no escaping the Earth, and no one is immune from disaster.
Sutter Buttes from the Sacramento National Wildlife Refuge, the remnants of a Cascades-style volcano in the Great Valley of California. Wait, what? A volcano in the Great Valley???

As we drove through Sacramento in the late afternoon, we could see the very strange skies produced by an out-of-control wildfire in the Coast Ranges. It was too close for comfort, and even as I write this fires are burning very close to the homes of friends in the Mother Lode (100 square miles and only 10% contained), and one of my most precious of landscapes, Kings Canyon in the Sierra Nevada, has gone up in flames (200 square miles already incinerated). In my life, these places will be forever changed, and for the lives of those in the path, their lives will be forever changed.

If geology and earth science teaches us anything, it is that we can't avoid disaster no matter where we go. You don't like earthquakes and volcanoes? Fine. Move to Kansas and enjoy the tornadoes, heatwaves and droughts (I used to say Oklahoma, but they have more earthquakes now than California). Move to Florida and enjoy the hurricanes and the unstoppable rise of coastal flooding. Every place on Earth that I know of faces some kind of event that is incompatible with human existence. And in a strange way, that's what makes us human: we evolved in a dangerous world, and occasionally we are reminded of this in tragic ways.

So how do we respond? Being the teacher that I am, I say the first priority is to educate yourself. Learn what geologic forces influence the place where you live. Learn what the real chances are of such events (don't depend on sensationalist sources in the media or the internet; they want viewership, and aren't really interested in actually educating anyone). Use the resources of the U.S. Geological Survey, or your state geologic surveys (except Oklahoma; for a long time the government there didn't allow the geologists to say that the earthquakes were man-made). Once you know what the threats are in your area, ask yourself what you would do to protect yourself if they were to happen today. Are you prepared? Can you make it through several days or a week or more without water, power, communications? Or the internet? What have you done to be ready? Or, will you be one of the many who will have to wait for the arrival of government assistance?

Am I trying to make you paranoid? Not at all. Paranoia comes from ignorance. If you know what could happen, and you have a plan, you've got the best possible chance to be okay. I can only relate the story of the time I came closest to death. It was two years ago on the Colorado River in the Grand Canyon. Because the river emerges from the deepest parts of Lake Powell, the river is at a constant 47 degrees or so, even when the ambient temperatures in the desert environment exceed 110 degrees. Hypothermia is one of the greatest dangers facing any river rafter. I was anxious about the possibility of a raft flipping in one of the rapids, because more than a few people have died in such circumstances. I worried, but I also practiced in my head, over and over, what I would do if it happened. And I never went into the river without a life preserver.

And of course it happened. We had come through dozens of huge rapids, and one could say that I was almost complacent as we approached Crystal Rapid, one of the two most violent rapids on the river. But the boat flipped in a heartbeat and I was in the river (see the whole story here). Knowing myself, I would have expected to panic, but the mental training took over instead. Although I was in the middle of watery chaos, I was able to get to the overturned raft, which made me easier to find, and I was positioned correctly when I started bouncing off boulders in the river. I was okay in the end, though very shaken. And it was because of the preparation and training provided me by my fellow travelers on the river.

And that's the message I leave with you at the end of this latest blog series. We all live on "dangerous ground". There is no place where we can escape the normal processes of the Earth. But we can choose where to live and what dangers to face, and prepare accordingly. And we can take care of each other when the disasters come.

I hope you've enjoyed the journey! I'll be compiling all the posts in one place soon.


Lockwood said...

Loved the series, and this conclusion is superb! Nicely done, sir!

Unknown said...

Very enjoyable and quite educational.
Thank you Garry, great ride!

Unknown said...

Very enjoyable and quite educational.
Thank you Garry, great ride!

Luisa said...

Thanks so much for this! Thanks also for the Compendium of Posts -- it's bookmarked for future reference. A great series, and an inspiration for this SoCal native to head north and look around.