Switzerland coordinates an extensive network of 600 seismographs stretching from Perpignan to Prague. The data obtained will enable better estimates of earthquake risk in Alpine regions.
Buried in a meadow, hidden in a barn and anchored at the bottom of the Mediterranean: 600 sensors placed on and around the Alps constitute the largest academic seismographic network in the world. The AlpArray project will enable better understanding of the birth of the Alps as well as homogeneous seismic hazard maps of the Alpine regions. Comprising 36 institutions from 11 countries, the project is coordinated by scientists at ETH Zurich and the University of Lausanne and is supported by the Swiss National Science Foundation (SNSF).
"We use extremely sensitive stations", explains György Hetényi, SNSF Professor at the University of Lausanne and first author on the publication detailing the implementation of the network.(*) "The stations can detect a mild earthquake in Japan, as well as thousands of seismic events that occur each year in Switzerland, 99% of which the population is unaware of."
The primary aim of the project is to better understand the structure and composition of the lithosphere (up to a hundred kilometres under the Alps) as well as the earth's upper mantle (up to 660 kilometres). It is at these depths that the traces of ancient ocean floors which are tens of millions of years old can be found. Tectonic movements continue at the surface and produce present-day earthquakes in Alpine regions, explains Hetényi. The collected data make it possible to compare and standardise the catalogues of events maintained by European countries, and thus to refine probability estimates for earthquakes.
Two thousand metres under the sea
Half of the network consists of existing stationary seismographs. The other half comprises mobile sensors, distributed during the two years of the project and placed both underground and in barns in high mountain pastures. "Convincing our partners to make so many stations available at the same time was not easy, but it's the only way to create this network and still keep costs under control. Only four countries had to buy new sensors."
Launched by Switzerland, AlpArray is managed by Edi Kissling and Irene Molinari of ETH Zurich, John Clinton of the Swiss Seismological Service and György Hetényi of the University of Lausanne. The Swiss part of the project is supported by a Sinergia grant from the SNSF.
The sensors were placed in a hexagonal network, analogous to the cellular structure of a beehive. "It was the most efficient way to achieve a dense geometry considering the fixed stations", explains Hetényi. "No part of the studied region is more than 30 kilometres away from a sensor." AlpArray extends more than 200 kilometres around the Alps, from the Pyrenees to Hungary and from Frankfurt to Corsica. Thirty sensors were installed at the bottom of the Mediterranean Sea. "It was only after fishing them back out last February that we got confirmation that they had worked properly, because the water column above them prevents wireless transmission", says Hetényi. The deepest station is 2771 metres under the sea; the highest is at an altitude of 3005 metres.
An "ultrasound" of the Alps
Mapping the Alpine structure is akin to doing an ultrasound: the sensors record the echo of seismic waves reflecting off the deep layers of the Earth. Comparing the arrival times of the waves at different sensors enables the researchers to triangulate the position of the layer as well as its composition, since the latter affects the propagation speed of the waves.
The recorded shocks come from small seismic events in Europe and moderate earthquakes all over the Earth. The network can even use ambient noise, such as from the swell of the sea, to obtain information about geological structures near the surface, down to a depth of a few tens of kilometres.
The AlpArray network has been fully operational since July 2017. Initial results are expected in 2019.
The stations of the AlpArray Seismic Network field experiment are collaboratively operated by the following institutions (alphabetical order): (alphabetical order): Czech Academy of Sciences, Deutsches GeoForschungsZentrum, Freie Universität Berlin, Geozentrum Hannover, Goethe University Frankfurt, Helmholtz Centre for Ocean Research Kiel, Hungarian Academy of Sciences, Istituto Nazionale di Geofisica e Vulcanologia, Istituto Nazionale Di Oceanografia E Di Geofisica Sperimentale, Karlsruhe Institute of Technology, Kövesligethy Radó Seismological Observatory, Ludwig-Maximilians-Universität München, Observatoire de la Côte d'Azur, Republic Hydrometeorological Service of Republika Srpska, Ruhr-University Bochum, Slovenian Environment Agency, Swiss Seismological Service at ETH Zurich, Università degli Studi di Genova, Universität Kiel, Université de Strasbourg, Université Paris Diderot, University Grenoble Alpes, University of Leipzig, University of Potsdam, University of Vienna, University of Zagreb, Westfälische Wilhelms-Universität Münster, Zentralanstalt für Meteorologie und Geodynamik.
In addition to the SNSF, the research was financed by the following institutions (alphabetical order by country: FWF (Austria); HRZZ (Croatia); Czech Academy of Sciences and CzechGeo/EPOS (Czech Republic); ADEME, ANR, Labex OSUG@2020 and RESIF (France); DFG (Germany); Development and Innovation Fund and Hungarian Academy of Sciences (Hungary); INGV (Italy).
G. Hetényi, I. Molinari, J. Clinton et al.: The AlpArray Seismic Network: a large-scale European experiment to image the Alpine orogeny. Surveys in Geophysics (2018) doi: 10.1007/s10712-018-9472-4 (Open Access)
Prof. György Hetényi
Faculty of Geosciences and Environment
University of Lausanne
Phone: + 41 21 692 43 21
https://link.springer.com/article/10.1007%2Fs10712-018-9472-4 'The AlpArray Seismic Network: a large-scale European experiment to image the Alpine orogeny.'
https://flic.kr/s/aHsmaJ27B1 'Pictures for editorial use'
http://p3.snf.ch/project-157627 'SNSF project OROG3NY'
http://p3.snf.ch/Project-154434 'SNSF project SWISS-AlpArray'
Medien - Abteilung Kommunikation | idw - Informationsdienst Wissenschaft
A promising target in the quest for a 1-million-year-old Antarctic ice core
24.05.2018 | University of Washington
Tropical Peat Swamps: Restoration of Endangered Carbon Reservoirs
24.05.2018 | Leibniz-Zentrum für Marine Tropenforschung (ZMT)
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
25.05.2018 | Event News
02.05.2018 | Event News
13.04.2018 | Event News
25.05.2018 | Event News
25.05.2018 | Machine Engineering
25.05.2018 | Life Sciences