Guess what, everyone?

That's right, it's Halloween!

Continuing a fine tradition begun only last year, I'm bringing you a collection of eerie, outrageous, and astonishing geology for all your spoopy All Hallows Eve needs.

Let us begin with...

Sharks in Volcanoes!

It's not a sharknado, but it just might be a sharkcano. Scientists recently found a sleeper shark living in an area that he wasn't supposed to be: in a volcano. The Kavachi is a very active underwater volcano in the Solomon Islands near Papua New Guinea, and when scientists sent down camera-laden robots to examine the volcano, they discovered far more than they expected.

Brennan Phillips, a University of Rhode Island Ph.D. student, was on this scientific expedition and described the scientists' reactions when they found multiple species of animals living in the volcano: "We were freaking out."

Well, I mean, obviously. You don't go into an active underwater volcano expecting to come face-to-ROV with a fricken shark. The inside of an active volcano is hostile to life at the best of times; add in the fact that you're dealing with water that can retain all that heat and acidity, and it's staggering that regular ol' critters that usually don't come up in conversations about extremophiles are just puttering about in there nonchalantly.

Now, there are few things in this world as incredible as an erupting volcano, and fewer still as awesome as an erupting submarine volcano, and virtually none as cool as an erupting submarine volcano that has got sharks swimming around inside of it, so please do treat yourself and go check out Kavachi on the Smithsonian's Global Volcanism page. Go on. You've earned it.

What can possibly top sharks in volcanoes? Nothing. So let's admit this isn't a competition, and turn our attention to our next example of haunting geology:

Ghost Forests

The story starts in the 1980s when geologist Brian Atwater, dendrochronologist David Yamaguchi, and others began to investigate the Pacific coast of Oregon and Washington. Traveling by foot and boat through the region’s many bays and river mouths, the scientists examined thousands of dead western red cedar and Sitka spruce. The trees had not fallen to the ground but stuck upright out of the sand in great groves, known as ghost forests.

Intriguingly, James Graham Cooper, a naturalist living on the Washington coast in 1853-1854, had noticed the dead trees, too. He thought they had died slowly, sinking into quicksand. Atwater, however, knew differently. When a magnitude 9.5 earthquake hit Chile in 1960, coastal marshes had dropped several feet, allowing sea water to flow in and quickly kill the trees.

Because the spruce and cedar still stood in place, Atwater and Yamaguchi realized they had a clock that would tell precisely when the trees died.

I mean, imagine, you're just a forest standing quietly on the coast, when suddenly and utterly without warning, there's a catastrophic shaking, and the sea rushes in, and the next thing you know you're dead for the next three hundred and some-odd years.

Cascadia, frankly, terrifies me more than any ghost story. You can read more about it here. I'm going to go hide under the bed for a bit before we go on our next phantom encounter...

Ghost Towns!

The town developed a fearsome reputation. In the harsh climate, there were few amenities besides drinking, and deadly conflicts were a constant part of life. One legend stated that a young girl, upon finding that she would be moving there wrote "Goodbye God, I'm going to Bodie" (a town has pride, and an editor for the local paper said the punctuation was wrong; she had actually said "Good, by God, I'm going to Bodie").

The mines were successful for a few decades, producing perhaps 2 million ounces of gold, but by 1913 the Standard Mine shut down, and people drifted away. 2,000 buildings were scattered across the valley, occupied by perhaps a few hundred people. A fire in 1932 destroyed most of the buildings, but 167 of them survived. Concerns about vandalism led to the establishment of Bodie Historical State Park in 1962, and efforts were made to stabilize what buildings remained. What's left is one of the most picturesque ghost towns to be found in the American West. The only residents today are a few rangers, and the ghosts. I'm not usually superstitious, but I would be just a little creeped out living there. I see the signs that say that all visitors must be gone by nightfall, and I wonder...why?

Ghost towns are utterly eerie and endlessly fascinating. Many of them dot the west and desert southwest, most old mining towns, founded on the vagaries of geology. Without a rich geologic history stretching into deep time, long before the prospectors came, most of these towns would never have existed. When miners depleted in decades what it had taken the earth thousands or millions of years to create, they left silent buildings slowly, silently moldering over the disturbed rocks and discarded minerals.

Sometimes, though, those towns reinvent themselves, and become very lively ghosts indeed, home to artists and eccentrics and people who just love to make a bit of history come back alive. In Jerome, Arizona, you can recapture a bit of that old mining spirit. But if you look beneath the wooden and metal bones, the detritus and creations of enterprising apes, you can discover an undersea volcanic story that makes sharks in calderas look positively pedestrian in comparison.

Let us end with a semi-appropriate song for the subject.

And so we come full circle. One more trip around the sun, my loves, and there will be ever more eerie, bizarre, and downright macabre geology to explore!