Saturday, December 28, 2013

On the Mount Pelee Volcano

Mount Pelee in the fog
A tiny reminder of lives lost in 1902
On the way there...lots of traffic
Mount Pelee is named after Pele, the Hawaiian goddess of fire. It is part of a volcanic chain at the edge of the Caribbean plate. This boundary contains seventeen active volcanoes including Mt Pelee and the submarine volcano Kick-'em-Jenny. The oceanic crust of the South American plate is being subducted under the Caribbean plate. 

We visited the observatory and later saw the volcano in the fog.  The observatory is part of the Institut de Physique du Globe de Paris. They do seismic monitoring, geochemical surveying and gather GPS data. The GPS network is about 2 years old and thus can only provide upper limits for the uplift of the crust of a few centimeters at best. There has been no gravity champaign ever performed on Mount Pelee - although some gravity data is available for the nearby volcanoes on the island of Guadalupe. Such a champaign perhaps will be carried on Martinique as well, but there are no immediate plans for one and no urgency for it.

nuee ardente (Heilprin 1902)
Photograph by Heilprin - 30.08.1902
Mount Pelee is a stratovolcano, which is shaped like a cone built from many layers from previous eruptions. It is characterized by explosive emissions unlike the cooled lava flows like those for the volcanoes in Hawaii.  This makes it very dangerous when active. The most dramatic eruption happened in 1902, which killed almost all the inhabitants (about 30, 000 people) of the city of St Pierre leaving behind very few survivors (the accounts of one prisoner, a shoemaker and a little girl were recorded). The officials declared that the city of St. Pierre was safe from the volcano because lava could not reach it. However, the nuee ardente, a type of pyroclastic flow, which is a fast moving cloud of hot gas and rock, reached a speed of over 670 km/hour and covered the city of St. Pierre in under a minute (see the Oregon State page of Mt. Pelee).

The black beaches of St. Pierre
The Mount Pelee volcano has shown no significant activity since its last eruption ended in 1929-1932. This latest eruption is
Me and Edward in front of Mt. Pelee
believed to be a second phase of the 1902 eruption. It could be that the volcano will be quiet for another 300 years or so, but there is no certainty of that, which is why the observatory in Martinique is still taking data. Also, even if there is no major eruption from previous history it seems that there is some activity every 100 years. Before the disaster of 1902, which had ample warning in the days before the eruption, there were precursory emissions in 1851-1852, 1792, 1635 (for a broad discussion of the eruptions see, for example, this pdf).  Although the volcano appears to be cooling and degassing, an eruption this century is not ruled out. The structure underneath the volcano is not understood. While there are some models, we do not know the shape/size of the magma chambers or how full they are. It is therefore important to keep observing.

Edward in the back of the observatory
The observatory
At the observatory we met with Dr. Clouard, who is one of the scientists in charge. In addition to volcano monitoring, she is also involved in Tsunami monitoring and prediction. She explained that while the world is currently afraid of Tsunamis because of the tragedies we witnessed this century, Tsunamis come in many sizes from a few centimeters to meters, and most of them do not inflict much damage. However, a substantial Tsunami would inflict major damage on small islands with a mostly coastal community like Martinique. It is therefore very important to continue the active monitoring and improve predictions & existent theoretical models, which often give poor predictions. The speed of such a wave can be between 650 to 850 km/h. This means that once an underwater volcano like Kick-'em-Jenny erupts, which is about 230 km away from Martinique, there will not be enough time to evacuate the island (see, e.g., on the vulnerability of the island to Tsunamis).

The last major earthquake in the area (magnitude 7.4, which is quite big) happened in 2007.
The rest of the team!

In the St. Pierre waters
Edward's first time swimming!

Saturday, December 21, 2013

In Martinique - Our First Tropical Vacation

We sent a few weeks in the Caribbean in the island of Martinique this winter. Martinique lies about 12 degrees from the Equator, which means it's always warm here - even now in December. However, we are still in the European Union! In fact, we are in France! Martinique is French territory. So, no visa or other strange paperwork was required. To get to Martinique, we took a 9 hour direct flight from Paris, and before that the TJV train from Zurich to Paris. It was a long trip, but totally worth it!

Piracy flourished in the Caribbean up to the mid-1800. Unfortunately, the big ship that appears slightly on fire in the picture does not belong to pirates. OK, I should say fortunately since pirates were neither as nice nor as good looking or as funny and charismatic as  Johnny Depp's Captain Sparrow. Oh... and the Pirates of the Caribbean movies were really filmed in Hawaii, CA, the UK, and a few other places, which did not include the Caribbean because to most people all beaches look the same.
Mihai and David playing in water.

We are renting a house in Grande Anse, a tiny village by the sea. The Martinique island is about 50 km across. Supermarkets and other modern commodities do exist on the island in Fort de France & other nearby cities. The village we live in only has a small local boutique and another store with beachwear that can be quite expensive. My hope is that a larger fraction of the money I spend reaches the providers. We do have Internet, two bathrooms, and everything seemed clean when we moved in. The Internet is really slow, and blogger keeps deleting and reposting this post at seemingly random times. Note that these Internet problems would be solved with a high performance fiber optics network that could also be used to monitor the island with atomic clocks. A simpler faster network would also do the job, but perhaps the tourists here spend more time on the beach than on the Internet.

Edward with a star fish.
The beaches in Martinique seem particularly beautiful to me. There are some tourists, but not enough to cover the beaches with blankets (and trash). The water is clear. The corals are amazing. Our landlord gave us glasses to go sea snorkeling. It's the first time I have ever seen the bottom of the sea, which is very colorful in a tropical island - we saw very many crabs, starfish, corals, puffer fish and some thorny black animals behind which regular fish hide. We ate coconuts that fell straight from the tree. They take quite a lot of work to open!

We succeeded in outwitting a crab and a fish with teeth! We tried to catch the crab in the bucket and that did not work because it kept jumping out. Then, with the help of a scuba diving lady, we found out that the crab liked to hang onto the bucket! Of course, we released it afterwards, but it's noteworthy that it took 3 physics PhDs + external help in outwitting a crab. The dead-fish-capturing entailed more physical exercise. Mihai found a fish buried deep in the sand, and Andy had to lift Mihai's legs to help him stay underwater to dig the fish out.  We wondered if it was hiding or reproducing there. However, upon closer inspection the fish appeared to not move or breathe. It was also fairly tiny. So, we threw it back in the sea.

Our next fabulous experience was to a walk to the next village.   We noticed that the grazing cows
Petting a cow with horns
had horns.  We even saw a calf that was not separated from his mother. This is unlike the civilized world where the horns are taken out to prevent the animals from hurting each other, and the calves are separated from their mother upon birth.

We then decided to hike back across the mountains. It was very rocky, and beautiful, but a little tough on the kids. David, Mihai,
Up the mountain barefoot
and I were also barefoot, which was  a challenge, but we made it. It also rained several times on the way there, but the rain was relatively warm and my big hat acted almost like an umbrella.

Under the double rainbow
It rains every day here for short periods of time and after it rains we can almost always see a double rainbow. I think I can get used to living on the beach in a warm place like this.

In Martinique, people have a very friendly and relaxed attitude. There is almost no concept of distance or time. We shop at a small store that brings a few supplies every day. By the evening there is very little left to buy.

We bought fish from a local fisherman - they had caught some 4 kg of fish, and we bought 2 kg for 20 Euros. They catch fish and crabs in small cages that lie under the sea. The fish and crabs get in, but then they fail to figure out how to get out. It's a fairly non-invasive way of fishing. As the dry season approaches with more tourists, they increase the quantity based on demand.

Saturday, December 7, 2013

In Warsaw at GR20

The library with Maxwell's equations
This post is obviously overdue since GR20 was a conference that happened last summer. But I thought it better to write about it now than never. The GR meetings are the biggest conferences in the field of gravitation. They are attended by many scientists from all over the world who give many oral and poster presentations. So, I  will not aim to describe everything that happened since that's impossible. I will just write about what I remember.
Mihai next to our apartment

I gave a talk on the atomic clock work and we also had two posters. One on cosmology and another on Chameleon models and STE-QUEST written by Andreas, my first student. STE-QUEST is a medium size mission candidate to be launched by ESA in 2022+. This mission would investigate the behavior of time and matter near Earth by using an atom interferometer and atomic clocks.

me on the day of my talk
In terms of setting, Warsaw is beautiful in July. We rented an apartment in a building with high ceilings that felt very much like being home. We each had our own room, and it was cheaper and better than a hotel. The "us in front road construction" pictures were taken for Edward and David who are still fascinated by bulldozers, and because Mihai and I like construction sites, too. We saw the benches that each played different pieces Chopin's music and the public library, which had art made from equations and a beautiful rooftop garden. The streets were full of people dressed in their national costume, who were performing in various ways. They were all surprisingly good looking (nothing like the beggars from other major cities). The restaurants were good, and served special dishes like wild boar soup.

While there was no scientific discovery that dominated the conference, there were a number of interesting talks. eLISA has just been selected by ESA to fly as one of the next large missions, and the development for LISA Pathfinder is almost done! The Pathfinder will be launched in July 2015 to test LISA technology. There is a proposal to extend the trajectory of LISA Pathfinder so that it can test alternative theories to dark matter (MOND & TeVes). These theories rely on the potential existence of some minimal acceleration that could explain the flatness of the rotation curves in galaxies without invoking a dark matter halo made from unknown particles.  The LISA Pathfinder will fly through the Sun-Earth Lagrangian L1 point to constrain these theories. At the Lagrange points the gravitational forces balance allowing the satellite to be stationary relative to the Sun and the Earth. The Pathfinder will be placed in a Lissajous orbit around L1, which is about 200 000 km from Earth and pass within 10 km or so of L1 at a speed of about 1 km/second.

There were some interesting presentations on atomic clock technology. While atomic clocks can be used to test gravity in various settings, they are very much a different field. However, I do believe they are important enough for every scientist to want to know more about them. The major breakthrough in clocks came a few years ago when they switched from the microwave band (1010 Hz)  to the optical band (1015 Hz). Some of the the best clocks now measure the frequency to 1 part in 1017 in about 30 minutes, which is pretty amazing. This means that they can measure the difference in tick rate between two clocks positioned 10 cm one above the other. The clock at the bottom will tick slightly slower than the one at the top. As part of the QUEST project there are developing a portable clock that is moved between PTB and Paris. They plan to measure the difference in the solid Earth tide via clocks. Tides shift the clock frequencies at the 10-17 level. The GPS clocks are all in the microwave band. They reach an accuracy of 10-15 after one day of integration, while an optical clock reaches an accuracy of 10-18 in 7 hours, which is about 3 orders of magnitude better. It's important to  propose ideas of using this clock technology on Earth and in space.

What will the future bring? I cannot predict the future (obviously), but it's always tantalizing to think about the next major jump! Clocks: Will they be able to switch from the optical band to the X-ray band? use transitions of the nucleus? charged ions? Or since there is no floor yet reached by current clocks through integrating longer, improving the technology may be sufficient for many years to come. An obvious desire is to see these amazing optical clocks made reliable, and portable enough to be used on a large scale (ideally without compromising their accuracy too much). The hope is to be able to use these clocks for practical purposes of interest not just to science, but to industry.

I attended some of the presentations on neutron star physics.  It was suggested that superfluidity could provide a natural cut-off for the r-mode amplitude at the order of 10-6, which would still cause significant heating of the star, or the movement flux tubes could in some way prevent such modes from growing. Their viscosity may also be increase by coupling to modes in the crust. It also appears that an active R-mode instability would heat isolated radio pulsars to higher than estimated temperatures. This is not a problem in accreeting systems since they are expected to be heated up by the accretion process anyway. This is a problem that is perhaps worth investigating.

The public lecture was on quantum gravity, where we learned that space is granular and that time does not exist (at Planck scale). The Big Bang could be a Big Bounce where after shrinking the universe will expand again. And, of course, infinities are not physical, the only thing that appears infinite to these really bright people is ignorance.

Mihai and I also spent some time talking to a Romanian colleague who was educated in the best Russian University from Siberia. It was very interesting. We got a glimpse of what deportation and relocation means - it's hard to think of losing everything in a few hours (or days) - including lives of (mostly children & elderly, but not only) people who could not survive the cold, property, money, friends. He had fought in the war in Transnistria from 1990s and has son who was attended Harvard. Deportation and relocation in places like Transnistria (a tiny country at the border between Moldova and Russia) can still happen for being on the wrong side of politics. The conditions are not quite as harsh as before and so (un)intentional loss of life happens less, but they lose everything else. I suppose that I should not be surprised, but I was because I forgot that such unfairness still exits so close to home. I don't even want to think about the many refugees from Syria or about the closing of the borders of Ukraine to perhaps thwart their many attempts to move towards the EU. On the bright side, this amazing gentleman we talked to is alive and now worries about mathematical formulas instead of guns.

The conference ended with a bus tour of Warsaw.  We saw flowers and people still praying for 96 members of the parliament of Poland who died in the plane crash in Russia in 2010 - although the bus did not stop there. Our guide talked about the aftermath of the second world war, which flattened most of Warsaw, and the afferent deportations/murders, and, of course, about some of their monuments and parks.   Most concentration camps (including the most notorious ones) were on polish territory. This is now a touristic attraction - although, nothing is left from them since they were all bombed in the end.