Were you naughty (or lucky) enough to get some coal in your stocking this Christmas? Congratulations! Coal is actually a fascinating rock, and tells us a lot about the geology of ages past in the locations where it’s found. And I mean, how often are you gifted rocks that burn? (Please don’t burn them, though.)
You probably wouldn’t expect Santa to be able to locally source his coal – after all, it’s a rock that requires swampy or marshy areas with lots of lush plants as raw ingredients for its formation. That’s not really what you find around the North Pole! But a mere 650 miles away, halfway to Norway, you’ll find an island chain that provides all the coal Santa would ever need. It’s the glacier-capped archipelago of Svalbard, and Santa wouldn’t even have had to go digging when he first went looking for coal. It was right in plain sight: (more…)
Now that we’ve got the geologic context of the Canary Islands as a whole figured out, it’s time to zero in on La Palma. How did she get here? Why are all the recent eruptions happening only on one half of her? What might be in store for the future? Does the fact that the most recent eruption is the longest and most voluminous of her entire recorded history mean the island is doomed? And is her active volcanic ridge, Cumbre Vieja, going to fall into the ocean and wipe out the East Coast of North America?
(I won’t keep you in suspense on that last one: the answer is almost certainly a resounding no. So while we’ll talk a bit about former collapses that have shaped the island, we won’t be spending any time on the megatsunami theory. Sorry not sorry.)
A Brief History of La Palma
La Palma is the second-youngest Canary island, and is still growing. She is, in fact, the most vigorously volcanic of the Canary Islands, boasting the most eruptions on record since the Spanish settlers arrived. And that’s just the last 500-ish years of her history: she’s actually about four million years old, if you count from her birth as a bouncing baby seamount. Nearly all of those years involve very hot rocks. (more…)
Do we have to do this again so soon? Really? Oh, geez.
Must we really, CNN? Credit: Dana Hunter
I’m not going to link that article, because while it does quote seismologist Harold Tobin up front basically saying nothing to see here, folks, everything’s normal on the Blanco Fault Zone, it also tries to scaremonger. And I’m so over the scaremongering.
There have been a lot of questions about the recent Blanco tranform activity, including whether these are related to volcanic activity in general, and Axial Seamount in specific. The short answer is no, these are definitively not volcanic quakes, but more detail follows.
First, the Blanco Transform fault is the most active fault in the Pacific NW, with very frequent quakes >M5. We can tell that these are normal Blanco faults by their location, by the way they fail (these are strike-slip earthquakes, consistent with the fault’s normal behavior, and happily, the type least likely to generate tsunamis).
There is no volcanism associated with transform faults. The nearest frequently active volcano (and the one people most often ask about) is Axial seamount, which is ~300 km from the activity we are seeing on the Blanco this week. This is much too far apart for these features to be associated with one another.
And I swear we all have to do this every dang time.
For anyone who’s been worried that this is the harbinger of something geologically awful in the Pacific Northwest, please be assured that it is not. This is absolutely business as usual on the Blanco Fault Zone. This is what it does. It’s not going to trigger the Cascadia megatsunami. It’s not even going to cause any minor inconveniences to the mainland. Volcanoes aren’t going to be triggered. Literally the only way it’s going to become an issue is if we decide to build a seafloor city right on top of it. Which, knowing humans, someday we will definitely do.
Just a hair over two years ago, my Scientific American article explained why the Blanco should be considered a fun rather than fearsome fault zone. I shall now reproduce that article here, because literally nothing has changed except the date. Please bookmark this to reference whenever someone starts freaking out over the Blanco’s latest antics. It’s all chill, folks. Just enjoy it’s little productions! Because they’re actually entertaining and informative from an earth science perspective, just the way we like our geology. (more…)
Hello and welcome to a new, semi-weekly feature in which I’ll share snippets of earth science news, cool things I’ve stumbled across, pretty pictures, status reports on upcoming articles, and whatever else seems interesting.
La Palma: Still on Fire
This has been one of the longest eruptions in La Palma’s recorded history, and is posed to be the longest, if it keeps going. Some of the recent lava fountains have exceeded 1,600 feet (500m) in height. The person who runs the GeologyHub channel has discovered a pattern in the data that suggests something interesting (and ominous to the locals) about the relationship between deep earthquakes and eruption activity on the island.
Can you believe where some of that ash ended up?!
It looks like the eruption may break some records. Interesting times indeed.
Hello, my lovely people! It’s American Thanksgiving, and hopefully most of us subject to it have survived without too many kitchen mishaps and family feuds. If you’ve spent it alone, I hope you’ve had a lovely bit of solitude. And for those of you who, like me, worked the day, I hope everything went as smoothly as a holiday can.
Let us give thanks to Tūtū Pele, who has provided us with this lovely and relatively safe ongoing eruption in her home on Kilauea volcano:
The last 24 hours of activity at Kilauea, as seen by the thermal webcam. Credit: USGS
A few days ago, I noticed a fairly large although fleeting increase in the output of lava from the summit vent. According to the USGS, it lasted just a few hours, and then all went back to the current normal. But it sure did look neat in the summit webcams! I grabbed the relevant bits and slowed them down for you.
So of course with all of the Iceland Volcano excitement, I had to run out and buy a bunch of books on Icelandic geology. It’s actually not super easy to find affordable ones in English. So I was very pleased to find one published by Springer for a good price: Iceland from the West to the South by Wolfgang Fraedrich. Springer is all about science written by scientists. I was stoked.
I have now read it, and…I’m considerably less stoked.
Halloween is here! This is my favorite part of fall: costumes, spooky stuff, decorating in black not only allowed but encouraged…. This is the holiday I was born for.
And I have some geology made for the holiday! This year, the theme is ghosts, and we’re going to visit some very ghostly geology and paleontology indeed.
1. Ghost Shrimp Haunts Ichnologist
This is a different kind of ghost shrimp than the ones under discussion, but it is metal enough for Halloween, so we’re rolling with it. Credit: Freddie Alequin (CC BY-SA 2.0)
Paleontology isn’t just about bones and preserved bodies: a branch of it, ichnology*, also looks at the things those bodies left behind, like fossilized trails, tracks, nests, burrows, borings, excavations, and even the divots left by pee. In this post, my favorite ichnologist, Tony Martin, talks about a very unusual trace he found that would be even more exciting to find in the fossil record.
Geologists love ghost shrimp, too, because of how their burrows are so numerous, fossilize easily, and are sensitive shoreline indicators. I wrote about this before with regard to how geologists in the 1960s were able to map ancient barrier islands of the Georgia coastal plain by looking for trace fossils of these burrows. Since then, geologists and paleontologists have identified and applied these sorts of trace fossils worldwide, and in rocks from the Permian Period to the Pleistocene Epoch.
I could prattle on about ghost shrimp and their ichnological incredibleness for the rest of the year, but will spare you of that, gentle reader, and instead will get to the point of this post. Just when I thought I’d learned nearly everything I needed to know about ghost-shrimp ichnology, one shrimp decided I needed to have my eyes opened to some traces I had never seen them make before just a few months ago.
*Not to be confused with ichthyology, which has to do with fishies. It’ll help to remember that ikhnos means “track” or “trace” in Greek, while ikhthus means “fish.”
The current eruption on La Palma in the Canary Islands is now over a month old. Already the island’s largest in a hundred years, it’s giving no signs of stopping just yet. Volcano lovers have thrilled to its spectacular Strombolian explosions. Residents have endured disruption, displacement, and loss of homes and livelihoods. Dogs trapped by lava flows had to be fed by drone before they were taken to safety in a daring and mysterious rescue. Living with a live volcano is far from easy and seldom safe.
Plenty of news agencies, vloggers, and blogs are keeping us up to date on the progress of the current eruption. I’m going to take us deep into the past, on a journey into the island’s origins and evolution. We’re going to see the slow, steady pas de deux between a mantle plume and the plate above it. We’ll watch underwater volcanoes go subaerial, building new land, and see catastrophic collapses tear their confections down. We’ll learn the life stages of a Canary Island, and by the end, we’ll know the broad outlines of La Palma’s destiny.
In the end, we’ll see that this current eruption is as much an act of creation as it is destruction.
Mirador de La Tarta, Tenerife. Yes, it’s literally called a cake! The white layer is pumice, the black layers are basaltic scoria, and the reddish-brown layers are oxidized basaltic tephra. Credit: H. Zell (CC BY-SA 3.0)
Allow me to set the scene: bugger-all was going on at Kilauea Volcano. Madame Pele had shut up shop in May and taken a luana iki (little rest). Perhaps she paid a visit to Iceland’s bouncing baby shield volcano. She may have stopped by La Palma to give her cousin some encouragement.
Back at Kilauea, there were a few rumbles in late August, with an intrusion of magma to the summit. But after that delivery, nothing much happened for most of September. It seemed to many that Pele’s luana iki might turn in to a long winter’s nap.
Madame had no such plans.
Timelapse showing the onset of the eruption. Watch the lower right tip of the island at the beginning – that frame is looped so you can see the uplift right before the vent opens. Click here for a full-size image. Credit: USGS
Kilauea’s most recent lava flows reached the sea over the weekend, and they’ve been beach bumming ever since. Few things are as dramatic as molten rock contending with seawater. We’ll be talking about all the neato things that are happening and that we may see if the eruption continues. We’re starting with LAZE, which in this case isn’t something you do on a hot summer afternoon. It’s this:
A dense LAZE plume rises from the Pacific Ocean during Kilauea’s 2018 eruption. Credit: U.S. Geological Survey
When blazing hot lava meets seawater, the interaction between them boils the water and produces enormous plume of mist, called LAZE (lava haze). These plumes are, of course, mostly water vapor, but they are so much more than that. They’re acidic beasts carrying appreciable amounts of hydrochloric acid, hydrofluoric acid, sulfate anion, carbon dioxide, and nitrogen dioxide, plus traces of volcanic glass and other particles. Even if you could find a safe place near where the lava is pouring into the ocean, you wouldn’t want to be hanging out there without industrial-grade protection.
Sounds super scary, right? Well, it’s concerning. But don’t panic. It, like so many of Kilauea’s other dangers, is something you can protect yourself against with a little common sense and caution. And it’s really pretty neat. (more…)
