Friday, May 13, 2011
Cataclysmic beauty and geologic inundations
Public domain image by Chris Ralph via Wikipedia
The Yellowstone volcanic hotspot first punched through the North American continent on the Nevada - Oregon border. There it triggered a cluster of caldera-forming "supervolcano" eruptions, which played out over a two-million year period. One of those caldera events entombed a forest of ginko and cryptomeria, which eventually mineralized into stunning black opals.
A surprising aspects of this process is that it wasn't just pebble-sized quantities of wood that mineralized into gemstone, but occasionally whole branches and trunks or even the skulls of snakes and other small animals.
So why a blog post on the supervolcanoes and gemstone trees?
At present I'm grinding away on finishing my first novella as part of a package of works that I will be publishing on Amazon and other digital book sites this year. Ashfall, coming in at around 150 pages, is a near-future techno thriller set in the aftermath of a Yellowstone super eruption that has buried much of the United States under destructive silicate ash and triggered a multi-year, global volcanic winter. Researching for this story has been by turns both horrifying and fascinating.
In a post last year, I discussed how a small supervolcano in Italy may have depopulated much of Neanderthal Europe and opened the way for modern Homo sapiens to expand northward. That and how an earlier Indonesian supervolcano dropped the world into a thousand year volcanic winter, which likely killed nearly 70% of humanity at a time when our numbers were already low. That same eruption buried much of the Indian subcontinent under three meters (nine feet) of ash, which is frightening considering not only the sheer amount of abrasive glass particle ash, but the distance of over a thousand miles that that airborne ash traveled.
Writing the current novella--as well as an earlier short story version of it that drew nice personalized rejections from editors--has been a challenge. In part, because of trying to portray a sense of optimism and human resilience in characters who are faced with what would be a vast, historic catastrophe. Also in trying to answer the question of how we could hope to survive such an event as a functioning technological civilization.
After all, it has been painfully clear in recent years that even catastrophes on a far lesser scale can challenge the world's most advanced post-industrial societies.
Ishinomaki, Japan. Public domain image, US Navy.
Writing about these kinds of massive events is also tricky because anticipating some of the more interesting and subtly destructive effects requires discovering how long-duration geological process can suddenly manifest human-scale effects. For the coast of Northern Japan, one of those effects is a consequence of the continental drift.
As pressure builds between colliding continental and oceanic plates, the coastline is pushed upwards over a span of centuries. Then it sinks in just minutes as that tension is released during a subduction zone earthquake and the ocean plate slides beneath the continent. In the case of Ishinomaki, Japan, that subsidence was four feet, and this coastal city now experiences daily flooding during high tides.
On a non-literary note, that same earthquake-driven subsidence is something practical for us to think about in here in the Pacific Northwest. Our last subduction zone event was just over three hundred ten years ago, and not only are there ghost forests of dead trees (pictures half way down the post) on our coasts that were abruptly dropped into the ocean thousands of years ago, but many beaches in Northern California are now close to twice as wide as they were at the beginning of the 1900s.
The uplift is taking place, and one day those stretches of strand will go down below the waves again in an episode of spectacular geologic violence.
One measured in just a handful of minutes.