AFTER WHAT HAS been a quiet 2015, Etna saw one of its first paroxysms of the year. Over the last few weeks, the Voragina crater on Etna has been restless, with low level Strombolian activity that was mainly confined to the crater. However, last night, the Voragine crater unleashed a lava fountainthat reached 1 kilometer (~3,200 feet) over the volcano with an accompanying ash plume that topped 3 kilometers (~9,800 feet). Even with all that intensity of eruption, the paroxysm was over in only 50 minutes.
This was Etna’s first significant eruption since May 2015, when the activity was centered at the New Southeast Crater, but the Voragine Crater had been sputtering lava occasionally since the start of the year.
In the ongoing conflict between science and creationism, evolution is usually a main point of contention. The idea that all life on Earth evolved from a common ancestor is a major problem for creationists. As a geologist, though, I think that the rocks beneath our feet offer even better arguments against creationism. For the creationist model doesn’t square with what you can see for yourself. And this has been known since before Darwin wrote a word about evolution.
What the rocks say
I don’t have to travel very far to make this case. There’s a slab of polished rock on the wall outside my department office that refutes so-called Flood Geology: the view that a global, world-shattering flood explains geologic history after the initial creation of Earth by God. This eight-foot-long slab is a conglomerate – a rock made from water-worked fragments of older rocks.
It’s what you’d get if you buried a riverbed composed of many different types of rock deep enough below ground for temperature and pressure to forge it into a new rock. Preserved in it, you can see the original particles of sand, gravel and cobbles made of various kinds of rock. And if you look closely you can see some of the cobbles are themselves conglomerates — rocks within rocks.
Why does this disprove the creationist view of geology? Because a conglomerate made of fragments of an older conglomerate not only requires a first round of erosion, deposition, and burial deep enough to turn the original sediments into rock. It requires another pass through the whole cycle to turn the second pile of sedimentary rock fragments into another conglomerate.
In other words, this one rock shows that there is more to the geologic record than creationists describe in their scripturally-interpreted version of earth history. A single grand flood cannot explain it all. Embracing young Earth creationism means you have to abandon faith in the story told by the rocks themselves. This, of course, is no surprise to geologists who have established that the world is billions of years old, far older than the thousands of years that creationists infer from adding up the generations enumerated in the Bible.
Early Christians read nature as well as the Bible
In researching my book The Rocks Don’t Lie: A Geologist Investigates Noah’s Flood, I looked into the history of thought about the biblical flood. What I found surprised me on two levels. First, most of the early workers who pioneered what we now call geology were clergy dedicated to reading God’s other book — nature. Second, in pitting science against Christianity, today’s young Earth creationists essentially ignore centuries of Christian theology.
For the first thousand years of Christianity, the church considered literal interpretations of the stories in Genesis to be overly simplistic interpretations that missed deeper meaning. Influential thinkers like Saint Augustine and Saint Thomas Aquinas held that what we could learn from studying the book of nature could not conflict with the Bible because they shared the same author. Yes, it seems that one of the oldest traditions in Christian thought holds that when reason contradicts favored interpretations of scripture about the natural world then those interpretations should be reconsidered.
In keeping with this view, mainstream Christians reinterpreted the biblical stories of the creation and flood after geological discoveries revealed that Earth had a longer and more complicated history than would be inferred from a literal reading of Genesis. Perhaps, they concluded, the days in the week of creation corresponded to geological ages. Maybe Noah’s flood was not global but a devastating Mesopotamian flood.
Young Earth creationists break from history
For over a century, such views dominated mainstream Christian theology until the twentieth century rise of young Earth creationism. This is the version of creationism to which Ken Ham subscribes – you might remember his debate with Bill Nye from 2014. Young Earth creationists imagine that people lived with dinosaurs and that Noah’s flood shaped the world’s topography. In fact, this brand of creationism, embodied by Ham’s Creation Museum in Kentucky, is actually one of the youngest branches of Christianity’s family tree.
Interestingly, one can challenge Flood Geology on biblical grounds. What did Noah do in the biblical story? He saved two of every living thing. So consider the case of fossils, which creationists attribute to the flood. What you find in the rocks is that more than 99% of all species entombed in the rock record are extinct. This simple fact offers a stark contrast to what you would expect to find based on a literal reading of the biblical story.
After looking into the long history of engagement and cross-pollination between geology and Christianity, I find it curious that the conversation constantly gravitates to arguments for and against evolution. Overlooked is how the young Earth creationist’s literal interpretation of biblical stories runs afoul of basic geological observations — like that slab of rock on the wall near my office.
A key point that gets lost in debates over the modern perception of conflict between science and religion is the degree to which this is actually a conflict within religion over how to view science.
The American Geophysical Union (AGU) is having its annual meeting now (Dec 15-19) in SF. With over 24,000 attendees, this meeting brings together the entire Earth and space sciences community for discussions of emerging trends and the latest research.
Lot’s of great updates can be found on twitter. Simply search/follow the hashtag #AGU14 (which, btw, is trending #1 at the moment). Here are a few examples:
If you haven’t had a chance to check out NASA’s Earth Observatory, do it now! Their mission is to share with the public the images, stories, and discoveries about climate and the environment that emerge from NASA research, including its satellite missions, in-the-field research, and climate models.
Amazing images and cool features every day. One thing to check out is their “World of Change“, which features images of the changes occurring to our planet over the course of several years. Some are depressing, others are quite fascinating. Here are a few to check out:
This past Saturday there was an unexpected eruption of Japan’s Ontake volcano. Below is a video of some first hand footage of the eruption. As usual, Erik Klemetti writing for Eruptions blog at Wired.com has the 411 on the eruption and why no one saw it coming.
Based on what I’ve read and seen (and this is speculation on my part), this eruption may have been a steam-driven explosion known as a “phreatic” eruption. The Japanese Meteorological Agency suggested that even compared to a smaller eruption in 2007, this explosion had almost no warning. This occurs when water seeps into the cracks in the crater area of a volcano and gets hot enough to flash to steam. This rapid boiling causes fracturing of the rock and explosively ejects material out of the crater as the pressure inside the crater or conduit goes up exponentially.
Klemetti reminds readers that there is no way to predict most volcanic eruptions, and thus not to blame volcanologists or the hikers for being there. Below are Klemetti’s tips for hikers who are planning a volcano hike, more detail at Eruptions blog:
How do you prepare yourself if you’re hiking in volcanic terranes? Here are a few tips:
Get to know your volcano.
Be doubly prepared.
Let people know where you are.
Understand the risk.
Mount Ontake, a volcano straddling Nagano and Gifu prefectures, erupted around 11:53 a.m. Saturday, leaving several hikers injured and stranded in mountain trails.
The Earth seems to have been smoking a lot recently. Volcanoes are currently erupting in Iceland, Hawaii, Indonesia and Mexico. Others, in the Philippines and Papua New Guinea, erupted recently but seem to have calmed down. Many of these have threatened homes and forced evacuations. But among their less-endangered spectators, these eruptions may have raised a question: Is there such a thing as a season for volcanic eruptions?
Surprisingly, this may be a possibility. While volcanoes may not have “seasons” as we know them, scientists have started to discern intriguing patterns in their activity.
Eruptions caused by a shortened day
The four seasons are caused by the Earth’s axis of rotation tilting towards and away from the sun. But our planet undergoes another, less well-known change, which affects it in a more subtle way. Perhaps even volcanically.
Due to factors like the gravitational pull of the sun and moon, the speed at which the Earth rotates constantly changes. Accordingly the length of a day actually varies from year to year. The difference is only in the order of milliseconds. But new research suggests that this seemingly small perturbation could bring about significant changes on our planet – or more accurately, within it.
In February 2014, a study in the journal Terra Nova showed that, since the early 19th century, changes in the Earth’s rotation rate tended to be followed by increases in global volcanic activity. It found that, between 1830 and 2013, the longest period for which a reliable record was available, relatively large changes in rotation rate were immediately followed by an increase in the number of large volcanic eruptions. And, more than merely being correlated, the authors believe that the rotation changes might actually have triggered these large eruptions.
Altering the spin of a planet, even by a small amount, requires a huge amount of energy. It has been estimated that changes in the Earth’s rotation rate dissipate around 120,000 petajoules of energy each year – enough to power the United States for the same length of time. This energy is transferred into the Earth’s atmosphere and subsurface. And it is this second consequence that the Terra Nova authors believe could affect volcanoes.
The vast quantities of energy delivered to the subsurface by rotation changes are likely to perturb its stress field. And, since the magma which feeds volcanic eruptions resides in the Earth’s crust, stress variations there may make it easier for the liquid rock to rise to the surface, and thereby increase the rate of volcanic eruptions.
The Terra Nova study is far from conclusive. Nevertheless, the idea that minute changes to the Earth’s spin could affect volcanic motions deep within the planet is an intriguing one.
But there’s another natural phenomenon which has a much stronger claim to affect volcanic activity – one which might be just as surprising: climate change.
Eruptions caused by climate change
In recent decades, it has become apparent that the consequences of planetary ice loss might not end with rising sea levels. Evidence has been building that in the past, periods of severe loss of glaciers were followed by a significant spike in volcanic activity.
Around 19,000 years ago, glaciation was at a peak. Much of Europe and North America was under ice. Then the climate warmed, and the glaciers began to recede. The effect on the planet was generally quite favourable for humankind. But, since the mid-1970s, a number of studies have suggested that, as the ice vanished, volcanic eruptions became much more frequent. A 2009 study, for example, concluded that between 12,000 and 7,000 years ago, the global level of volcanic activity rose by up to six times. Around the same period the rate of volcanic activity in Iceland soared to at least 30 times today’s level.
There is supporting evidence from continental Europe, North America and Antarctica that volcanic activity also increased after earlier deglaciation cycles. Bizarrely, then, volcanic activity seems – at least sometimes – to rise and fall with ice levels. But why? Again, this strange effect might be down to stress.
Eruptions cause by the melting of ice
Ice sheets are heavy. Each year, Antarctica’s loses around 40 billion tonnes. They are so heavy, in fact, that as they grow, they cause the Earth’s crust to bend – like a plank of wood when placed under weight. The corollary of this is that, when an ice sheet melts, and its mass is removed, the crust springs back. This upward flexing can lead to a drop in stress in the underlying rocks, which, the theory goes, makes it easier for magma to reach the surface and feed volcanic eruptions.
The link between climate change and volcanism is still poorly understood. Many volcanoes do not seem to have been affected by it. Nor is it a particularly pressing concern today, even though we face an ice-free future. It can take thousands of years after the glaciers melt for volcanic activity to rise.
Yet while it may not be an immediate hazard, this strange effect is a reminder that our planet can respond to change in unforeseen ways. Contrary to their brutish reputation, volcanoes are helping scientists understand just how sensitive our planet can be.
Robin Wylie does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.