We live on a geologically active planet. This, of course, isn’t a shock to anyone but sometimes seeing just now active it is can be fascinating. ESRI put together a dynamic map (above) that captures worldwide volcanic activity over the past 10,000 years in just over 90 seconds. The planet lights up like a Christmas tree with eruptions of all sizes!
When you watch the video, a few things become apparent. Volcanism is concentrated in a lot of places you tend to associate with eruptions: Indonesia, New Guinea, Japan, West Indies, Kamchatka in Russia, Alaska, the Philippines, , the Marianas, the Andes (although not the whole length), Central America, New Zealand, Hawai’i and Iceland.
Most of those (other than Hawai’i and Iceland, both of which are above mantle plumes) are places where an oceanic plate is being jammed back into the mantle as it collides with either another oceanic plate (for example, the West Indies) or a continental plate (for example, the Andes). We call these boundaries subduction zones. When these collisions occur, we get a lot of magma produced and with it, volcanoes.
However, there are likely a few spots that catch people by surprise. We can see multiple eruptions over the past 10,000 years in places that are unexpected, like American Desert Southwest (Arizona, Utah, Nevada), northern Iran and Turkey, Sudan, the Arabian Peninsula, North Korea and Taiwan. Although in many of these places it has been thousands of years since the last eruption, that is a blink of an eye for the life of a volcano, so we should expect that new eruptions might happen there in the future.
Let’s dispel one misconception that might come out of this video map: volcanic activity is not increasing. What is increasing is our awareness of volcanic eruptions, so even small burps from a volcano get recorded.
Much of the volcanic activity included in this map prior to a few hundred years ago comes from the geologic rather than historic record. Small eruptions don’t tend to get preserved in the geologic record, so they are not accounted for in the past. The record is, overall, biased towards large eruptions and eruptions near populations. As there are more people and better communication, we know about more eruptions.
Another missing piece in our planet’s volcanic lifestyle is the mid-ocean ridge system. This tectonic boundary, where two plates are moving away from each other as lava erupts between them, is spread across tens of thousands kilometers at the bottom on the oceans. There have been a multitude of small eruptions along the mid-ocean ridges over the past 10,000 years, but unless we happen to be thousands of feet beneath the surface of the oceans to see it happen, we miss that in the volcanic record.
What this map really captures is that, other than Jupiter’s moon Io, the Earth is hands down the most volcanically-active body in the solar system. For that, we can thank the heat produced inside the planet that drives plate tectonics. As we move into more and more places on the planet, we need to be ready to live with the fact that the planet is dynamic.
The Earth’s ice caps, in Greenland and Antarctica, are an invaluable record of climate over the past hundreds of thousands of years. As each annual layer of snow falls, gets buried and eventually becomes glacial ice, it traps particles and gases from the time it fell. We use that record to examine how the atmosphere has changed.
These cores turn out to be one of the most important pieces of evidence we have that global carbon dioxide levels in the atmosphere have been rising significantly. However, ice cores can also capture brief moments in time where massive events leave their mark on the planet.Read More
Carbon dioxide! Little did we realize 100 years ago how this simple gas would become such a cultural lightning rod. Yet here we are, in what might be an existential fight focused on how much carbon dioxide humans pump into Earth’s atmosphere. It isn’t a little bit, either. No, humans might now be the gold standard in carbon dioxide emissions in the history of the planet.
Let’s get a few things straight: Carbon dioxide has been around since the planet formed. It has been part of our atmosphere in varying concentrations and appears to play a profound role in how the planet’s climate varies over time.
The Earth is actually chock full of carbon (the ultimate source of carbon dioxide). New work by the Deep Carbon Observatory estimates that the planet holds over 1.8 billion gigatonnes of carbon. That number is hard to fathom, but when you think about all the carbon locked in rocks and minerals, it is still less than 0.1% of the planet’s mass as a whole.Read More
We seem to now live in an age where people are comfortable ignoring experts, especially those in the sciences.
You may have noticed that Hurricane Dorian didn’t hit Alabama. Depending on the circles in which you run, you might think it was a “close call” or a completely mistaken statement that Alabama was ever in any real danger from the hurricane. However, what is clear is that when experts in meteorology — the National Weather Service — made it clear that Alabama was not in peril, they were rebuked by a presidential administration who clearly holds scientific expertise in contempt.
This country, and some would argue the world, has started to drift away from trusting expertise. What do I mean by that? I mean people who have been trained and vetted in their knowledge and interpretation of information. A medical doctor is an expert on parts of the human body. A climate scientist is an expert on the planet’s climate. A meteorologist is an expert on the weather. A mechanic is an expert on how to fix your car. It is all expertise.
When we turn away from expertise we put ourselves and others in peril. That holds whether it be because we believe in conspiracies, the information experts present is in opposition to our worldview, or that we made a mistake and don’t want to own up to it out of pride.Read More
Alaska is full of volcanoes. Most of them lie along the long, arcuate chain along the Alaska Peninsula and Aleutian Islands, stretching far into the Pacific Ocean. However, they are not the only volcanoes in the vast state. to the east of the Aleutian arc are the Wrangell-St. Elias Range. It is one of the most complex tectonic area in North America and home to at least 10 volcanoes. In fact, some of the largest eruptions in the past 10,000 years come from the Wrangell-St. Elias range.
Why bring this up now? Well, the Alaska Volcano Observatory announced the installation of a new pair of seismometers for Wrangell. It is the most active volcano in the Wrangell-St. Elias Range, most recently erupting in 1912. We now have the ability to watch for signs of new eruptions from Wrangell.
Wrangell is big. The shield volcano is over 30 kilometers across and hosts multiple nested calderas at its summit. Some of these are formed from potential large explosive eruptions in the volcano’s past, others may have been formed by a more gradual collapse like we saw at Hawaii’s Kīlauea last summer. It has also produced lava flows that travelled almost 60 kilometers from their source!Read More
There isn’t another planet in the solar system like Earth. If you were an alien explorer coming into our neck of the galaxy, you’d find a system with four large gas giants, lots of small, rocky objects without much other than rocks, a few larger rocky objects with some ice and four rocky objects with reasonable atmospheres.
A cursory scan of the surface of those last objects would find that two of the four are covered almost entirely in basalt — an iron and magnesium-enriched lava. You run into this stuff everywhere. The third is actually the moon of another planet and seems to be made of basalt, ice and some liquid methane. However, the last of these objects is not only mainly covered in liquid water, but the rocks … oh, the rocks.Read More
So, first off, I apologize for the clickbait headline, but don’t worry, there actually is a payoff here. What I’m going to say is 100% true. Geology isn’t just a pile of rocks, no matter what you might think. Sure, there are rocks involved … but “geo” doesn’t mean rocks. It means Earth, so when we talk about geology, we’re talking about the our planet — and our planet is more than rocks.
Don’t get me wrong. I love rocks. They’re tiny (and really huge) packets of history. They are time capsules left by our home planet for us to figure out. They are a greatest hits and deep dive into the discography of the solar system. Incomplete, sure, but captivating, intriguing, born long before us and existing well after we will.
What do I mean that geology isn’t rocks? I think we need to change how we all think about geology. Certain famous scientists and TV shows liken geology to stamp collecting (or not even a “real science”). This is, of course, nonsense, but it is the perception. Geologists (and paleontologists) go out and find rocks, minerals, fossils, slap a label on them and cache them away in museums or dusty drawers. It is born out of a Victorian idea of the discipline.
However, the last time I checked, it isn’t 1875. Geology has changed a lot since the time of cataloging and description. What is the modern science of geology?Read More
Over the last few weeks, we’ve had two newsworthy events that involve volcanoes and water. This is a common combination on our planet and can have dramatically different results. One is a very small feature that’s new to one of the most active volcanoes on Earth. The other is now a large feature spreading across the Pacific that came from a previously unknown volcano under the sea.
First, the small: the US Geological Survey has been reporting on a new crater lake forming in the Halema’uma’u caldera in Hawai’i (see above and below). It has been almost a year since the last eruption at Kīlauea and as I’ve reported, the summit area might have experienced the most dramatic changes during 2018.
Since then, things have been pretty quiet. The summit area regularly steams with fumaroles thanks to the heat of the volcano and access to groundwater. Remember, when the lava lake at Halema’uma’u drained during the start of the 2018 rift eruption, explosions started when the lake drained below the water table. So, the new collapsed caldera at the summit has some points below that water table … and now one of those pits is filling with water.Read More
Copper is one of the most valuable metals on the planet. Sure, it lacks the cachet of gold, silver or platinum — those are “precious metals” after all. Yet, without copper, the world as we know it would not operate. If you have electricity, you need copper.
This week, Rio Tinto and BHP Billiton, one of the world’s largest mining companies, were given permission from the U.S. Forest Service to move ahead with the Resolution prospect near Apache Leap in Arizona. This would become the largest copper mine in North America once the mine is operational in the 2020s.Read More
Earlier this month, I spent a little over a week exploring one of the biggest mysteries in then Cascade Range. It’s a string of volcanoes spanning from Northern California into British Columbia and host to such well-known peaks as Mount St. Helens, Hood and Shasta. Yet, some of the largest eruptions over the past million years in the Cascades may have come from volcanoes that are totally hidden from view today. One of those mystery volcanoes is the Tumalo Volcanic Center.
I’ve been fascinated by the TVC since I was in graduate school. We would take field trips from Oregon State University to visit the area around Bend in central Oregon. If you’ve never been to Bend, you’re missing a true volcanic wonderland. The city is built on layer after layer of volcanic rock that goes back millions of years.
Some of the volcanic features are very young (geologically-speaking), having formed in the past few thousand years. This includes basaltic and rhyolite lava from Newberry, steep cinder cones like Mt. Bachelor and sticky rhyolite domes like the Devil’s Hills along with the ash and pumice from the TVC.Read More