My wife and I often enjoy picking up college courses recorded by The Teaching Company. We recently picked up a new geology course that has the latest research on the state of the field these days.

Wow, what a fascinating topic. It's amazing how much there is to learn, and how we know what we know, and how the development of the field has affected our understanding of biology, cosmology, and so on.

We picked up the course on DVD (some courses are also available in audio-only formats), figuring that the visual nature of the lectures might be of interest to our budding young scientist, Alexander. By way of planning for an upcoming family outing to Mt. St. Helen's, we skipped ahead to a lecture regarding the eruption of this volcano in 1980.

The volcano and its activity since its most recent eruption are fascinating, but the lecturer also went into the tectonic activity that makes this region ripe for a catastrophic earthquake. I've known for years now that when Mt. Rainier blows, we'll likely have a couple of months warning, but the eruption could produce lava flows (floes?) as far north as Seattle. In fact, we live in an area that was partially hit by Rainier two eruptions ago.

[For those who don't know: Mt. St. Helen's is south of Rainier, putting it closer to Portland, OR, but still rather nearby.]

What I didn't know was that our local region was wiped out by a 9.0 magnitude earthquake just over three hundred years ago. Because of the way the Juan de Fuca fault works here, we are already entering the "danger zone" for the next catastrophic quake. That said, it's more likely that the next big one will hit in 100 to 200 years (these big'uns tend to hit four-hundred to five-hundred years apart), but we're still entering dangerous geological times.

The instructor of the course gave a compelling argument that Seattle and Portland are likely to be destroyed within the next couple of hundred years.

This isn't necessarily as scary as it sounds. History contains several examples of cities destroyed by a catastrophic event, only to be rebuilt. Such examples include San Francisco after it's big earthquake (and subsequent fire) of 1906 and the devastation of Tokyo and Yokohama following the 1923 Great Kanto earthquake.

Then again, the above mentioned earthquakes measured a mere 8.0 on the Richter scale, and they *did* kill hundreds of thousands of people. I don't know if I'd necessarily prefer to be hanging around when a 9.0 hits. While Seattle and the surrounding areas will certainly be rebuilt following a major volcanic eruption or earthquake, I might be inclined to miss the main event that leads up to a new and improved city.

For all that, though, when it comes to being the most dangerous city in America, Seattle certainly stakes a strong claim, geologically speaking.

Los Angeles, eat your heart out.