The world’s most ill-begotten piece of real estate

Gulf of Naples (Campi Flegrei Caldera) with Vesuvius in the background.

Few cities on the planet can even start to compete with Naples in being ominously placed from a geological standpoint. The city has not only a tremendous historical background; it is also totally surrounded with active super volcanoes.

A few years ago I had the pleasure of having dinner in a villa on the slopes of Monte Vesuvius together with Italy’s car tycoon numero uno. After a tasty dinner together with nice wines we were sitting looking out at the ocean drinking a ridiculously old grappa (grappa tastes like a rotting hamster-cage smells) and I just had to ask if he never where worried about having a villa on one of the worlds more famous volcanoes. The answer was rather Italian; He turned around, raised all five fingers into the air in the general direction of Vesuvius and uttered the Italian immortal phrase “va’fan’culo”. I interpreted it as “who cares”. Actually it is a bit stronger than that in translation.

Vesuvius residing within the Monte Somma Caldera.

But in a way it summed up the Neapolitan view on their 3 troublesome super volcanoes. To hell with them. Basically this opinion explains why the citizens even do their best to impede scientific work on their volcanoes. In 2010 the mayor of Naples stopped drilling into Campi Flegrei to increase the monitoring of the volcano.

Naples has more than 4 million inhabitants in the greater Naples urban area; at least 1 million of them are directly threatened by the 3 giants under them. In theory there is a plan to evacuate the citizens, but 3 factors would most likely hamper any evacuation.

Image by NASA. Campi Flegrei seen from space.

The first one is of course the issue with the “va’fan’culo” attitude against their volcanoes. Most likely many would not heed an evacuation order in time. The second issue showed itself during the Campi Flegrei inflation periods of 1970 and 1984 to 1985. Back then inflation pushed Pozzuoli up more than 3.3 meters, and still only an area of 10 city blocks was evacuated. This points to it being likely that political pressure would impede any scientific call for evacuation before it was too late. The third reason is quite simply the poor state of the road network in and out of Naples. There is just no way to evacuate 1 million people in the stipulated 3 days. An amount of time that could well be quite less after the usual Italian political infighting.

Not even mighty ancient castle walls are protection for Naples.

This was the first part out of a 4 piece special. In the next 3 I will go through all 3 super-volcanoes in turn. Since all 3 of them are so different, and pose so different types of risks they deserve at least one post each.

Now you are most likely going, where did he find a third super volcano? Well, that will become clear in the next post.

CARL

Sheepy Dalek – Name that Lava VIII

Lava of the Week!

Last week got a bit confused due to the mix-up of the two pictures. This time I have made triple sure that the picture shows the same as the answer.

The Score is:
3 Diana Barnes
2 Talla
2 Ursula
2 Doug Merson
2 Hattie
1 Schteve
1 Jim
1 Luisport
1 Heather B
1 Birgit
1 Jamie
1 Henrilerevenant
1 UKViggen

This week’s competition

I will award one point for the correct name of the volcanic system, one for the volcano, one point for the eruptive vent, and the final point for the lavas (minimum two correct lava types).

This week I want the name of the volcanic field, the volcanic formation on the picture, and of course the lava. So 3 points to go for.

Call for post-texts

I am soon going to become pretty occupied since I will be preparing to move, and also with work. So, if you have a good idea for a blog post, please do not be shy. Who know, you might become the next Alan.

CARL

Dead horse

The 2012 Super-moon. The largest full moon in 18 years. And no, it did not cause any large earthquakes either.

What exactly does that mean? Well, having a dead horse, in more modern navy slang, is having a debt that comes out of your pay to cover short term loan that the paymaster gave to you. It’s money you don’t see until it’s paid off. There’s nothing wrong with it, you should always pay your debts, but that is just a term that is applied to it. It comes from older nautical days when sailing was prevalent. If your ship was becalmed for extensive periods, odds are, you would run out of feed any livestock that you were transporting. The last thing you want laying around while you are stuck waiting for the wind… are dead horses. I’ve been around the stench of decaying animal copses (MV Livestock Express in the Red Sea) and it is not a pleasant aroma. (the Livestock Express had about 300 sheep stacked in one corner and couldn’t dump them due to environmental regulations)

Yeah, it’s an obtuse approach to the meat of this, but it is related… sort of.

The Horse latitudes are between about 30 and 35 degrees latitude. It’s pretty close to the boundary that I used in this chart.

Image by GeoLurking.

In case you missed it, this is one of the follow up charts that I used down in the discussion in the Moonie post. And, since I’m beating a dead horse, I felt the intro was appropriate.

That chart is a plot of the major plate boundaries between 30°N and °N and 30°S. It’s also the region traversed by the apparent sub Lunar and sub Solar points. That means that they both pass directly over head in this region at some point during the year. (plus about 5° of slop just to make it even)

Edward Lane at April 22, 2012 at 14:54 brought up a good point that spurred me back into thinking about the forces at work on the different ends of the plate boundaries. As many of you remember, I mentioned that if there were an effect, that there should be a physical explanation for it… at least an idea of a mechanism. Something that could be examined to see what the merits of the parent idea were. (Solar/Lunar influence).

Simplifying that plot into something that we can sort of measure, you get this:

Image by GeoLurking.

This is the angular measure of the extents of the plates in longitude as measured from the center of the Earth. The vertical boundaries are misleading, they actually get closer to each other the further from the equator they go. But for getting a general idea of their size, this works.

Now, since the Moon is pretty close, and it’s generally the most touted astronomical body that influences seismic activity, let’s look at what it’s effects might be.

Gravitational acceleration on the surface of the Earth is 9.8 m/s per second. This can also be expressed as N/kg of force. (9.8 N/kg). What is the comparable acceleration effect of the Moon on an object on the Earth? Roughly 0.00003319 m/s² towards the Moon.

How about the variation from one end of a plate to another, allowing for the extra distance from the Moon? Well, for a 30° plate, from directly under the Moon to the end furthest away… 0.00000015 m/s² less.

Here it is in graphic form:

Image by GeoLurking.

Referring back to the rectangular boxes on the plates… the largest extent was about 114°. That plate has an acceleration difference from the Moon of about 0.00000150 m/s², or ten times greater than the 30° plate.

Either way, that variation in force from the moon is still about 0.0000153% that of the gravitational force from the Earth.

This also explains why the researchers who have found a Lunar effect on some already seismically active areas have such a hard time extracting that signal, it is excruciatingly small.

GeoLurking

Distant earthquakes and volcanoes

Photograph by NASA. Grimsvötn 2011 eruption seen from Space.

The world is filled with people believing that large earthquakes cause volcanoes to erupt far far away. Lately we have had quite a few very large earthquakes that all where above 8 in magnitudes and two that was on the mega-colossal scale (Tohoku and Boxing-day earthquakes).

Here is the list since 2000:

2001: June 23 Peru (8.4)

2003: September 25 Hokkaido Japan (8.3)

2004: December 23 Macquery Islands New Zealand (8.1), December 26 Sumatra Indonesia (9.1 Boxing day earthquake)

2005: March 28 Nias Indonesia (8.6)

2006: May 3 Tonga (8.0), November 15 Kuril Islands Russia (8.3)

2007: January 13 Kuril Islands Russia (8.1), April 1 Solomon Islands (8.1), August 15 Chincha Alta Peru (8.0), September 12 Sumatra Indonesia (8.5)

2009: September 29 Samoa Islands (8.1)

2010: February 27 Maule Chile (8.8)

2011: March 11 Japan (9.0 Tohoku)

2012: April 12 Sumatra Indonesia (8.5), April 12 Sumatra Indonesia (8.2)

Good, now we have raw data. Among these are 6 out of the 11 strongest earthquakes recorded by man. One of the earthquakes was the third largest earthquake ever recorded. If something could rock the boat it would be one of these ones. Oh, and before you go off on the “there are more earthquakes now than before train”, no it s not. It is just that we have far more seismometers available now.

Photograph by M. Rietze. Stunning image of Eyjafjallajökull 2010.

What do we need now? Well, a couple of smoking close to eruption volcanoes would be good. Iceland is bound to have a couple. So let us check for the usual suspects. We had 3 eruptions happening (2 Grimsvötn and 1 Eyjafjallajökull). On top of that we have Hekla who is achingly close to erupting since 2007; Hekla is most likely the closest volcano on the planet to tipping over into an eruption. And for fun, let us throw in Etna; she is always up for a show.

Let us start with Grimsvötn, the penultimate bad-boy of Iceland. Grimsvötn has had more eruptions than any volcano during the last 300 years, and also the world’s largest fissure eruption during the same time period. We should find something there should we not?

2004 November 1? Nope, nothing happened then. 2011 May 21 (Grimsvötns largest eruption in a century). Nothing spectacular happening on that date.

Now you are going, Eyjafjallajökull, she disturbed airline traffic and was a messy bastard, surely that one was caused by an earthquake? 2010 March 17 (Fimmvörduhals-eruption) and April 14 (Eyjafjallajökull crater eruption). Well, I am sorry but nothing happened then.

Photograph by Nasa. Etna in full swing.

Let us now go for Etna, she is having loads of small eruptions during this time-period, so statistically at least one should coincide with a large earthquake. Let us check. I am not going to write a long list of the eruptions, I will just write down those that occurred that coincides with an actual earthquake. And once again it shows that no major eruption coincides with an Earthquake. If we then go into the last eruption of Etna that started in August 2010 and is still ongoing we find that Etna had series of small eruptions called Paroxysms. These happen about monthly so one of them would surely be a jackpot.

Lo and behold! We have a match! After 10 days of being quiet Etna had a paroxysm in the morning of the 12^th of April. Thank the Gods, we have proven that Earthquakes causes Eruptions!

Or did we really? No we did not. Etna is a very predictable volcano, and Dr. Boris Behncke had already warned about the eruption coming 36 hours before the earthquake. Hm, so the volcano was already going to erupt. In reality the eruption was actually not coupled that well with the earthquake, there was 4 hours in between them.

Image by Icelandic Met Office. Here you can see the effect of the initial 8.5M Sumatra quake. The sinusoidal effect on the plot is earth-tides. The amount of energy shown for the quake is 10 000 times less than during the 2000 eruption of Hekla.

Well then Hekla, the most trigger happy volcano on the Planet. Locked and loaded to go off since at least 2007, one would think that nasty mess of a volcano would do something. Well she did, she shivered as jolly pudding. Here you can see both the 8.5 and the 8.2 earthquakes. It is a nice image, it shows that there is enough lava down there to actually shiver like a pudding, otherwise it proves nothing. The last eruption produced a motion 10 000 times larger. So, if the volcano closest to a large eruption on the planet did nothing more than behaves like Jell-O I would say that this matter is over with.

An Earthquake cannot cause an eruption in a far off volcano. Get over it.

Bonus volcano, Mount Merapi! We should not be euro-centric.  Guess what, there were no earthquake then either.

Merapi at work.

Why?

It is actually quite simple, the waves generated are filtered by the vast mass of earth, when the waves from the earthquake finally arrives only the most low in frequency are left, and they span a lot of area, we are talking about waves that are 100s of meters wide up to kilometers wide. They do not cause a kick in the ass of the magma causing it to de-gas, instead it gently sloshes it a bit. Like the difference of dropping a beer-can on the floor and opening it, and gently pulling the tap and pouring it after having turned the can gently upside down a few times.

If you do not believe me about the filtering try this experiment. Put on your favorite recording on your loudspeakers. Tape a piece of cardboard over the tweeters, listen. You should now hear that the high frequencies are muted. Now repeat the same thing over the bas. Not much happening right? Now, let us have fun, put in some earplugs before doing this. Now go and crank up the volume and take a look at the cardboard. It should by now be pulsing with the base pretty visible. Gosh darn it; same does the earth do to the earthquake waves.

The gently rocking motion of a teleseism (distant earthquake) is quite reminding of the gentle slow-moving earth-tides. And they do not cause eruptions either (nor earthquakes), but that is another bedtime story for another evening.

Earthquake on Earthquake

The same principle also goes for Earthquakes. A distant Earthquake is not going to cause a distant fault-line to rupture. Why? Well again the waveforms are so large that they move all of the fault-line at the same time in a slow and equal movement. Think here about going for a massage and compare it to being hit a few times by a boxer. The massage does not really hurt you, but the boxer will.

In this case the boxer was the blow of 8.5 at Sumatra, it damaged a close by fault-line causing the following 8.2 Earthquake. So I am sad to say that physics do not allow teleseisms to set off series of large earthquakes all over the planet. Get over it 2012ers.

CARL

Photograph by Eggert Nordahl. All copyrights reserved. For usage contact Volcanocafé. This beautifull picture shows Hekla in the late evening a few days ago.

The Moon and the Moonie

Part I: The Moon

This is getting a bit old. Time and time again, someone bops along with the idea that the Moon or the sun causes an increase in seismicity. They climb up on their soapbox and thump their chest denouncing the world (that would be the rest of us) are blind to the obvious correlation. That we will all suffer ruination if we don’t heed their warnings or suffers some calamity akin to a slow and brutal death.

Hey, sounds like fun. Let’s play.

Here is a plot of all earthquakes greater than Magnitude 4.5 as listed on the USGS website from 1973 to 2010.

Image by GeoLurking.

Wow, that look a bit compelling. How about the power distribution across that same data?

Image by GeoLurking.

Well… that seals the deal. Right?

Not so fast.

First, I would like to point out that there is some research that points to a lunar influence in the activity of certain already seismically active regions, but that this research is founded on actual science. The effect is ephemeral and buried in noise. This is not intended to debunk that research, only to illustrate just how misleading some of the source data is, and how easy it is to jump to conclusions.

Now here is the nugget-o-truth that most people tend to miss:

The longer that the Moon spends at a specific location, the more likely it is that quakes will occur while it is at that location.

The Moon completes an orbit around the Earth about every 27.321 days. All orbits have a Perapsis (closest point on orbit) and an Apoapsis (furthest point). At perapsis the Moon is at it’s highest rate of speed at about 1.076 km/s.1 At apoapsis, it is moving at 0.964 km/s1. Obviously, this speed is not constant. The period of the Lunar orbit is 27.321582 days2 . The Moon goes through a full phase cycle in about 29.53 days3. That’s almost the same period… but it’s not. Couple this with the dynamics of an elliptical orbit, and you get this odd characteristic.

Image by GeoLurking.

This is the dwell time of the Moon on two separate phase cycles. Notice that the curves, though similar, do not match. This is due to the ‘not quite the same’ durations of the phase cycle and the orbital period. Also notice that the amount of time spent at the New and Full phases is longer than at mid phase.

Let’s take a look at several cycles in order to see if there is a pattern.

Image by GeoLurking.

Sure enough… that orange is the plot of several phase cycles. The blue is an average of what is seen at that phase over those same cycles. (the average of the orange curve). We can go a step further and run this through a curve fitting program in order to see if there is a function that matches.

Image by GeoLurking.

That’s pretty good… but note the end points, even though the curve is a good fit, it leave enough uncertainty on the ends to make it mostly useless. I provided the plot mainly since I pissed away about two and a half hours in Erueqa’s “Formulize” in order to find it. (it’s a really great program though).

Taking the idea of using the mean of the curve to calculate a correction factor, and using the 1000 bin average from the previous plot (the one with the orange and blue), we can apply that to the quake count curve.

Image by GeoLurking.

Err… where did the trends go? Okay, maybe the power curve will still show the significant signal.

Image by GeoLurking.

Hmm… not looking so good.

There is still an artifact in there… at least it seems to me like there is an artifact in there… but it’s small. So small that the last thing I would do would be to stand on a soap box preaching at people about it.

Part II: The Sun and the Moon

I realize that some people are adamant about the seismic connection with the Sun and the Moon. I also realize that I have pointed out a few issues with making this connection. One might argue that I was being very selective in presenting the data… okay, fair enough.

Here are some more plots that may, or may not, show a connection. You be the judge.

Image by GeoLurking.

Image by GeoLurking.

Image by GeoLurking.

Image by GeoLurking.

Nothing there that really jumps out at ya eh? Okay, a few more:

Image by GeoLurking.

Image by GeoLurking.

Do note that the apparent dwell time of the Sun at mid Winter and Mid Summer really stands out in that last plot. By the way, see those horizontal bands? Those are the latitudes of seismically active areas.

Continuing…

Image by GeoLurking.

Image by GeoLurking.

Again, the bands equate to known active areas… this time in longitude.

You may think me an ass for not believing in the Sun-Moon-Earth connection. That’s your prerogative. But unlike some, I actually went out and looked for myself. I’m not one to buy a pig in a poke. Personally, I don’t see it in the data. If your numeric skills are better, knock yourself out. I could stand to learn a thing or two while reading it. But if it’s BS, I’m not gonna buy it.

GeoLurking

1) http://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html

2) http://en.wikipedia.org/wiki/Moon

3) http://en.wikipedia.org/wiki/Lunar_phase