“Tsunami are water waves generated by earthquakes, underwater landslides, volcanic eruptions or major debris slides,” said Dr Rossetto. “The waves travel across oceans with small vertical displacements and in open water you could easily bob over one without noticing. It’s when the waves approach the coastline, hit shallower water, slow down, and grow taller that you get the huge wall of water that people visualise when you mention a tsunami.
“The main gap in our knowledge is about what happens when the tsunami wave approaches the nearshore region and then runs inland. These flow processes cannot be simplified using mathematical models because of the complex interaction that takes place with beaches, sediment, coastal defences and then in and around buildings.
“It is possible for the whole process to be simulated with hydraulic models, but to get meaningful data the tsunami wave has to be accurately generated in the first place. Conventional wave generators haven’t been able to replicate tsunami because of the unusually long wavelength that is required.”
Professor William Allsop of HRW said: “Our new machine will control the flow of a large mass of water by using air suction within an inverted tank. We have used this technology over many years to make model tides in large scale models and our collaboration with UCL means we will be able to produce a unique research facility.”
The new tsunami generator will be able to create multiple waves, replicating the three or four peaks experienced during the Boxing Day tsunami that hit the Indian Ocean in 2004. The tsunami will pass down a 45m long flume at realistic wavelengths, mimicking the characteristics of waves which have passed from deep water (approx. 200m) into shallow water (20m – 50m) as they approach the coast. The wave flume will be equipped to measure coastal processes, inundation and wave forces as the tsunami travels up a shelving seabed, breeches the coastline and flows inland.
After the initial series of experiments, a team of researchers from UCL and HRW will go on to examine the effects of retreating and repeated waves on seawalls and beaches. The tests will measure the force exerted by the waves on representative buildings and quantify the wave’s ability to erode the coast, potentially destabilising structures completely.
The tsunami experiments will take place at HR Wallingford’s laboratories in Oxfordshire and construction of the generator is scheduled for completion in the summer of 2008. UCL and HRW plan to make the facility available to international teams of researchers in autumn 2009.
David Weston | alfa
In times of climate change: What a lake’s colour can tell about its condition
21.09.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
Did marine sponges trigger the ‘Cambrian explosion’ through ‘ecosystem engineering’?
21.09.2017 | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
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