Saint Barbara - or why geoscientists are a celebratory bunch

Today is December 4th, which is known in many places as the day of Saint Barbara, or simply "Barbara Day". Traditionally, at least in Germany, we cut a couple twigs of our Forsythia in the backyard (the "Barbara twigs"), and put them in the living room in a vase. The 20 days until Christmas and the warmth of the room are just enough to make the pretty little flowers of the Forsythia twigs come out in time for Christmas Eve. The bright yellow flower blossom is supposed to be a sign of good luck for the new year.

Now you're gonna be sitting there thinking:

Why the heck is she telling us about some Saint and a plant and Christmas traditions?

Turns out the Saint after which December 4th is named, Saint Barbara of Nicomedia (Turkey), is the patron saint of miners, and generally of people who work (and/or live?) in the mountains. The legend behind this can be told in a few sentences: Barbara (your average teenage girl in the 200th century) decided to be a Christian, her father didn't like it, she fled town and hid in a crack in the rocks, was found, was killed, but then her father was killed by lightning... in other words, the usual. She may be the patron saint for miners because of the lightning, or because of her hiding place in the rock. 

What matters more is the fact that if she is the patron saint for miners and other people in the mountains, that includes - by extension - the geologists/volcanologists, and maybe even geophysicists. When you're doing your geosciences undergrad degree in Munich, you sure don't wanna miss the legendary "Barbarafest". Every year in early December (not always exactly on the 4th...), all the geology/geosciences/geophysics students get together for a night of partying in honor of our good old friend Saint Barbara. Of course, as you can imagine, a lot of the original story behind this tradition is lost, but in spirit we're definitely honoring her by having all sorts of geology related fun. Despite the fact that my undergraduate years were quite a while back, I still remember the Barbara celebrations very vividly. Even more so, my memory got refreshed recently: My awesome little cousin is following in my footsteps and getting a geosciences undergrad in Munich. Go, Jara! She's a first-year, so like every first-year before her (including myself) she will have to go through the "geology baptism". Geologists are a happy, sometimes slightly alcoholic bunch, so the baptism will most definitely include some minor (?) drinking components. Of course, geology challenges like using your rock hammer in an (entirely non-)appropriate manner and other fun activities are included - all thanks to our good old friend, Saint Barbara. Sounds like fun to you? Make sure you don't go too crazy at the Barbarafest though, you might wanna have some left-over energy for the famous "Geolaus" celebration on December 6th, just next door at the other university in Munich. Of course, taking place in deeply catholic Bavaria and all, this celebration is also in memory of one of our good old Saints, this time we're talking about Saint Nicholas (Bishop of Myra). But maybe we'll save this story for another time...

You see, geoscientists in Germany are clearly very conscious of important religious occasions, long-lived and beloved traditions, and they are generally quite a happy and welcoming bunch (assuming that you survive the geology baptism...). Do geoscientists in other countries have the same celebrations? Or are there even more Saints that are celebrated by geologists worldwide?

One final little curious detail: Some sources say that Barbara is also one of the patron saints in Sicily, because she is believed to have protected the town of Catania from Etna's lava flows. So basically one could say she's also a volcano saint. Who knew? Maybe I should be putting her picture in the corner of my blog.

A photo of a church window depicting Saint Barbara and a miner or mason (who could equally be a geologist... I mean, look at the hammer!). Photo: GFreihalter

Sources:
http://www.katholisch.de/de/katholisch/glaube/unser_kirchenjahr/weihnachtsfestkreis/heilige_barbara.php
http://www.heiligenlexikon.de/BiographienB/Barbara.htm
http://en.wikipedia.org/wiki/Saint_Barbara

Mini series on volcano hazards - part II: From blows to flows...

So last time we talked about the ash the comes out of the volcano when it blows its top. We said that volcanic bombs can be unpleasant when they hit you - to put it mildly. We also discovered that the ash goes up in the air and eventually (slowly) falls back down and creates some serious problems.

Now unfortunately the ash doesn't always slowly come back down to the ground. An ash cloud is a mixture of broken up pieces of magma of different sizes (remember? Ash, lapilli, and bombs), and a bunch of hot gases. The volcano spits out that mixture, and when there is a lot of the hot gases and not quite as much ash the mixture rises up into the air. It can go quite high, and then get transported with the wind and create a big mess for air travel (which we saw happening all the way from Iceland to Europe 4 years ago). Why does the ash cloud rise up so high? In very simple terms it's the same principle as a hot air balloon: The mixture of hot gases and ash is less dense than the surrounding air, so it rises. Sometimes, the amount of ash in the ash cloud is too much though - so the mixture can't rise. Instead it does what every heavy object does when you throw it up into the air: It comes back down, sometimes really really quickly. When this happens we call it a "pyroclastic flow" (from the Greek words for fire and broken in pieces). Check out the video from Earth Uncut TV below to see what a pyroclastic flow looks like.

As you can see in the video, these pyroclastic flows can get quite fast. With speeds of several 100 km/h, they're too fast to drive away from in a car. They're also quite hot: The mixture is almost as hot as the lava that comes of the volcano, something like 600-800˚ C. That's over 3 times hotter than the temperature in your oven when you make pizza. So imagine something that hot hits you at speeds faster than a race car. You can imagine what the outcome would be... In 1991, the Japanese volcano Unzen erupted and created a pyroclastic flow that (in)famously killed over 40 people, including Katia and Maurice Krafft, a couple of volcanologists. 

Has anybody seen the movie Pompeii that came out a few weeks ago (at least in North America, some places in Europe etc might have to wait a bit longer...)? It's based on a true story of a volcanic eruption and a pyroclastic flow of Mount Vesuvius in 79 AD. The pyroclastic flow from that eruption covered the city of Pompeii and everybody in there in several meters of ash. People's bodies were preserved in that ash, and at the historic site in Italy we can still see their casts in the positions they took in the last seconds of their lives that ended so abruptly almost 2000 years ago - a stark reminder of the power of volcanic eruptions.

Below another video (timelapse, by Photovolcanica) of a pyroclastic flow from Sinabung in Indonesia earlier this year. This particular one had a different trigger mechanism - the collapse of part of the volcanic edifice during the eruption. The outcome, however, can be as devastating as the pyroclastic flows generated by ash clouds. In fact, e.g. the Japanese example above was a pyroclastic flow created by a collapse of a part of the volcano.

As we will see next time, pyroclastic flows aren't the only flowing hazards on volcanoes. Water, ash, dirt, and bigger particles can create lahars, and of course lava itself can flow down the slopes of a volcano. But we'll save these topics for another time.