Friday, June 8, 2012

What Geology Can Teach Us

Welcome Accretionary Wedge readers. This is a slightly updated version of an article I wrote three years ago on the subject of how we live with geology. Even if you're read it before, it might seem new. ;)

Caption: There goes Yellowstone - again.

Image credit: Screenshot of Faces Of Earth by Cujo359 (See Note below)

On Dana Hunter's recommendation, I borrowed a copy of the television mini-series Faces Of Earth. It's quite a series, if you're interested in science or the world around you. I'll just let Dana summarize:

It's all science, having been produced by the American Geological Institute and supported by the American Association of Petroleum Geologists. Don't worry - it's not an advert for Big Energy. In fact, if they meant it as an advertisement for more drilling, it's probably going to do quite the opposite. Once you've experienced several hours of Earth's geological majesty, you're a little less inclined to destroy it.

Sunday Sensational Science [April 19, 2009]

An episode that I found particularly interesting was "Building America". In this episode, some of the geological events that formed the continent we now live on are described using interviews with scientists and lots of computer graphics. What struck me as I was watching the episode was how catastrophic for our economy and society some of those events would be if they occurred now.

Empires Rise And Fall

As biologist Jared Diamond observed in his book Guns, Germs, And Steel, in many ways geography is destiny. As the PBS introduction to the series says:

At the heart of Jared Diamond's Guns, Germs and Steel are the stories of apparently commonplace things, such as wheat, cattle, and writing. Diamond believes the uneven distribution of these simple elements shaped the course of global history and played a vital part in the epic story of continental competition.

Diamond also focuses on the physical geography of the world in which we live. For instance, natural impediments such as mountain ranges or bodies of water created isolated civilizations.

He argued that continents which were easily traversible, such as Europe encouraged trade among different people and stimulated development.

Guns Germs And Steel: The Story Of ...

Europe benefited from a mild climate, nearness to the places where horses, oxen, and other animals were domesticated, and the places where agriculture began. It translated those advantages, combined with the advantage of being so open to the sea and isolated by some geographic features, that it almost had to explore the rest of the world.

Even so, Europe hasn't had everything its way. Mt. Vesuvius, for instance, helped end the western Roman Empire. The bubonic plague reached it several times, thanks to its contacts with Asia. One of those plagues helped end the eastern Roman Empire. But Europe was lucky. Isolated from the Muslim empire by the Bosporus, the Dardanelles, the Danube River, and the mountainous southeast of Europe and too distant from the empires of Asia, Europe survived long enough to develop the technology and the domesticated animals it would use to conquer much of the world.

It could be worse. Europe could have gone through the event that ended the Akkadian empire - a century-long drought.

This screenshot is of archeologists digging at Tell Leilan, a site in modern-day Syria that was an Akkadian city more than 4,000 years ago. According to the program, the artifacts indicate that the city was very advanced for its time. They had standards of measurement for food portions, for instance. They also indicate that the city was abandoned rather suddenly. Soil samples in the area show signs of the drought. Ice core samples taken in the Andes Mountains in South America confirm that this drought happened, as do the contents of sediments in Arabian lakes.

While a great deal isn't yet known about the nature of the Akkadian empire, it's clear that their society couldn't cope with the onslaught of their neighbors. It wasn't alone. As Wikipedia points out:

Ancient Egypt

In ca. 2150 BC the Old Kingdom was hit by a series of exceptionally low Nile floods, which was instrumental in the sudden collapse of centralized government in ancient Egypt.[12] Famines, social disorder, and fragmentation during a period of approximately 40 years were followed by a phase of rehabilitation and restoration of order in various provinces. Egypt was eventually reunified within a new paradigm of kingship. The process of recovery depended on capable provincial administrators, the deployment of the idea of justice, irrigation projects, and an administrative reform.

Wikipedia: 4.2 Kiloyear Event

Recovery from disaster required a competent government. Where could we have applied that lesson, I wonder?

Things went south much more quickly for the Minoans. A volcanic eruption on the nearby island of Theros helped speed its demise. According to the Wikipedia entry, it was one of the largest eruptions in history. While only a small amount of ash fell on Crete, it is likely that the disruption the volcano caused for ocean traffic helped weaken the Minoan empire.

(Re)Building America

This episode of Faces Of Earth was the one that hit closest to home, so to speak. It discusses several geological processes that helped shape America's geography.

One of these processes is the subduction zone off the Pacific Coast. This zone, where the Juan de Fuca tectonic plate is pushed under the North American Plate, has been the site of several huge earthquakes. It is illustrated in the image to the left. As the drawing shows, this is also a zone of highly active volcanos.

Geologists study and monitor this area in a variety of ways. As the episode shows, they are planting a network of seismometers throughout the region to track tremors, quakes, volcanoes, and other signs of the earth shifting. They use this information to gain an understanding of what happens before and after these events, and to try to determine signs that a big, and potentially disastrous, event is on the way.

Image credit: screenshot of PNSN Recent Earthquakes in the Pacific NW page by Cujo359

One outcome of this research is the Pacific Northwest Seismology Network web page. The first place many Northwesterners go after the ground shakes is the recent earthquakes page, of which this is a screenshot:

This map covers an area that includes three large cities (Seattle, Portland, and Vancouver, BC), and many smaller ones. Any of these cities could be endangered by a volcano or major earthquake. Knowing more about how these things happen could, even in the short run, save many lives and reduce their economic consequences.

Caption: Mt. Rainier, one of many active volcanoes in the Pacific Northwest.
Image credit: Cujo359

The Puget Sound region, in particular, could be endangered by its proximity to Mt. Rainier, an active volcano:

About 3.5 million people live and work in proximity to Mount Rainier. Many residents of this region may be unaware of the hazards posed by the volcano. Wholesale, permanent evacuation of the region around the volcano (large parts of Pierce, King, Lewis, and Cowlitz counties; see Figure 2.1) would be necessary to completely eliminate risk to life and property from the volcano. Obviously such an approach is unrealistic and unworkable. The communities in the region must seek ways to reduce risk to life and property from volcanic hazards while maintaining the strong economic base that derives in part from the desire of people to live, work, and play around the volcano.

Mount Rainier: Active Cascade Volcano (1994)

As bad as a major eruption of Mt. Rainier could be, it pales in comparison with some other potential volcanic events. One of them is illustrated by the graphic that leads this article. It's an artist's conception of the eruption of the Wyoming megavolcano. To get an idea just how "mega" this event could be, that yellow outline surrounding the eruption is Yellowstone National Park, which covers an area roughly 75 miles (120 km) square. As a Discovery Channel article on this volcano relates:

A modern full-force Yellowstone eruption could kill millions, directly and indirectly, and would make every volcano in recorded human history look minor by comparison. Fortunately, "super-eruptions" from supervolcanoes have occurred on a geologic time scale so vast that a study by the Geological Society of London declared an eruption on the magnitude of Yellowstone's biggest (the Huckleberry Ridge eruption 2.1 million years ago) occurs somewhere on the planet only about once every million years.

What's Under Yellowstone: A True Hotspot

A U.S. Geological Service report provides some details of how large these eruptions were:

The ash flows erupted at the climax of each cycle form the three largely welded cooling units of the Yellowstone group, providing a framework for the stratigraphy of the volcanic field. The 2,500-cubic-kilometer Huckleberry Ridge Tuff erupted at 2 million years ago, the 280-cubic-kilometer Mesa Falls Tuff at 1.3 million years ago, and the 1,000-cubic-kilometer Lava Creek Tuff at 0.6 million years ago. Each of these great eruptions produced fallout ash deposits over large parts of the western United States, leaving recognizable remnants as far east as the Mississippi River. The first and third cycles were sustained by enormous bodies of rhyolitic magma that accumulated to batholithic size, the highest parts of each intruding and deforming its roof to form compound ring-fracture zones. When a major eruption began from one of these high-level portions of the batholithic chamber, the violent degassing triggered contemporaneous or successive eruptions from the adjacent or overlapping ring-fracture zones, producing composite ash-flow sheets and compound calderas that embrace the cluster of ring-fracture zones.

Yellowstone Caldera, Wyoming

By contrast, the Mt. St. Helens eruption produced less than three cubic kilometers of ash and landslide.

As the Discovery Channel article points out, no one expects this volcano to erupt soon, but when it does it will be immense. Given the uncertainty in the time between eruptions, there's no reason to think it couldn't happen a century or two from now. Starting to learn about this phenomenon now is essential, because when it does happen, it will reduce the United States to a Third World country, and will severely affect climate around the world.

Yet another danger is represented by this graphic. No, that's not the infamous K-T event, in which a large asteroid or comet hit Central America and brought about the end of the dinosaurs. It's an artist's re-creation of an asteroid hitting what is now the Chesapeake Bay roughly thirty-five million years ago. It dug a crater roughly 12 miles (20 km) wide and 4 miles (6.5 km) deep, as noted in this National Science Foundation (NSF) article:

With the Chesapeake's soft mud sediments, however, the crater walls weren't strong enough to support such a massive pit, said [USGS geologist Greg] Gohn. "The walls began to fall in on themselves, trapping the salt water within the collapsing mass of rocks and sediments."

Gohn, Ken Miller of Rutgers University and colleagues recently completed three months of round-the-clock drilling into the crater. The scientists retrieved rock samples from a mile down in the impact structure.

What they found surprised both geologists and biologists.

"The cave-in of the perimeter stirred up nutrients that eventually allowed microbial life to blossom inside the crater," said Gohn. "This was the first sampling ever conducted of microbes within a crater."

Crumbling Walls of Ancient Chesapeake Bay Crater Threaten Regional Groundwater Supplies

As the title of that article notes, this crater that was formed and disappeared long ago is still affecting life on this planet, including human life.

This is the location of the crater this strike formed. That's Hampton, Newport News, and Norfolk, Virginia, on the left end of that circle. Right at ground zero is the tip of the Eastern Shore peninsula. Thirty-five million years later, it's hard to tell that there ever was a crater. Yet we learned there was, because geologists were looking for oil there.

This seismograph illustrates what geologists saw in the bay, a crater buried under a quarter mile or so of mud and sediment. As the NSF article relates, in 2008 many core samples were taken of the area. What they discovered is that, among other things, a colony of microbes has been growing there, in a place where they typically aren't expected. They also found that the material that forms the crater may have a significant impact on the water supply in the region:

For human life, however, the finding that the crater's walls had at least partially caved in isn't good news. Salt water that was trapped within the crater now threatens the water supplies of those in the region.

"The water inside the crater is no longer completely fresh," said Miller. "In fact, the water is twice as salty as surrounding seawater."

Many towns and villages in the Chesapeake Bay region rely on underground freshwater aquifers that flow through the crater. Their wells could become "contaminated" with salt water.

Crumbling Walls of Ancient Chesapeake Bay Crater Threaten Regional Groundwater Supplies

The USGS maintains a warehouse full of the cores that have been dug out in the area that surrounds the crater. Without this effort, there would be no warning that drinking water might soon be affected. We certainly would have less understanding of how life might have formed on other planets in impact craters.

We can learn a lot from digging in the mud.

Had they existed at the time, Washington, DC, Richmond, VA, Baltimore, MD, and Wilmington, DE, would all have been either destroyed or severely distressed by such an event. Certainly, Philadelphia, New York, and Atlanta would have experienced some damage or serious financial impact, as well.

Image credit: NASA

This was not the only asteroid or comet to ever hit what is now the United States, only the biggest. This is a photo of the meteor crater near Winslow, Arizona. It was formed by a smaller impact 20,000 to 50,000 years ago. That's a very short time in geological history, and came at a time when human beings were starting to spread out over the planet. The first humans came to North America only a few millenia later than the end of that estimated impact period.

What Should We Learn From All This?

There are two very important lessons that we must learn from all this if we are to survive as a nation and as a species. The first is that calamity can happen to anyone, as it did to the Romans, the Akkadians, and the Minoans. It has happened to many others. It can happen to us.

One of the unspoken assumptions in discussions I have with many Americans who don't feel that we need to obey international law, or even follow our own beliefs about how we should treat others when it comes to how we treat the rest of the world, is that we will always be big enough to have things our own way. Somehow, either because their god will protect us, or just because that's the way things are, they assume things will always be that way. If there's anything that events like Hurricane Katrina and other disasters should already have told us, it's that no place is safe. No one in this country, and in the rest of the world, can honestly say that his home can't be destroyed or terribly damaged by a natural event. The events I've listed here aren't hypothetical - they've happened before and they will happen again. How we've treated the rest of the world when we were big will determine, to a great extent, how we're treated when we're reduced by such an event.

The other lesson is that this is why we do science. This is why we provide money for people to dig in the ground for fossils, old cities, and just to see what's in the mud. It's why we explore space. Yes, there are starving bankers and auto executives who can barely afford health care, but this is important, potentially life or death stuff. The discoveries in one field of science help to illuminate mysteries in another field. No field of knowledge is so obviously inconsequential that it can be ignored. All legitimate scientific inquiry deserves to be funded, because if someone can imagine the question there's probably a good reason to know. The only argument should be how much we can afford.

We humans have a precarious existence on this planet. It might seem otherwise - to us the Earth seems huge and indestructible. To some extent, it is. There are many things that could change, though, that could make our lives somewhere between difficult and impossible. We need to know everything we can possibly learn about our world and the universe it is a part of. Knowing what can happen can lead us to try to prevent it, or to minimize the consequences.

Geography is destiny, and as geology teaches us, geography is always changing. It doesn't have to change for our benefit.

So, the next time some god-bothering imbecile, some demagogue, or some New Age airhead asks why we need to fund all that science stuff, clue him in to this fundamental truth:

We do it so we can survive.

NOTE: Unless otherwise noted, all images in this article are screenshots of the television Faces Of Earth. The producers of this series are in no way responsible for this article, nor did they approve or endorse it.

UPDATE (June 7, 2012): I've updated this article for its inclusion in the Accretionary Wedge #46. In particular, I made these changes:

  • Updated the references to, and screenshot of, the Pacific Northwest Seismology Network's recent earthquakes page.
  • Added photo of Mt. Rainier.
  • Added the "read more" break
  • Added link to Meteor Crater photo story
  • Changed one huge run-on sentence in the conclusion to two not so huge sentences.


Anonymous said...

A good reminder, there are possibilities that are greater than us and not too far removed from happening or happening again.

Jared Diamond's Collapse reminds us that great catastrophe isn't required, something simple as lack of rain brings down the house, as many civilizations bones attest.

There is no assurance the capability exists to survive, happenstance determines many outcome either positive or to the detriment. How good is your civilization at using the tools given its disposal? That is for substantially rational civilizations; the god(s) do not insure irrational civilization's survival. How is your country's hubris today?

Thanks for the reminder, history is written, moment by moment, the geologic record is the library where the manuscripts of history are kept.

Cujo359 said...

Maybe the most important lesson of Collapse is that civilizations can often choose to adapt to a changing situation, or to change its ways when it's clear that things can't continue as they are. Knowledge, especially science, is important, but then so is the willingness to act on that knowledge. There, too, we see troubling signs that we aren't up to that challenge as a people.