“The model we have developed can be used to predict tsunamis that form following the sudden fall of sediments near the coast”, Enrique D. Fernández Nieto explains, who is one of the authors of the study and is from the Department of Applied Mathematics from the University of Seville. Rock-fall can be favoured by the existence of an abrupt slope at the bottom of the rock-fall, by an accumulation of material, or by a strong surge that destabilises the layer of sediments and causes it to fall.
The study, which has appeared in the Journal of Computational Physics, uses equations known as “Savage-Hutter equations” named after the two scientists who proposed these in order to study rock avalanches. “However, for the first time we are addressing the need to take into account the coupling between the two layers implicated in the processes of submarine avalanches: water and rocks”. This is how Fernández describes it and also considers that studying this two-layer coupling “is complicated, but fundamental to the total dynamic, because rock movements cause the water to move, and possibly the tides of water that can displace granular material”.
Like columns of water and sand
In order to derive the model, the mathematicians took into account the porosity of the sediments, the forces that interact in the process and the “Coulomb friction term”, which refers to the parameters of the equation that are opposed to the movement of the mass of rock when it falls.
In order to understand this concept, Fernández cites the example of a column of water in a container, the door of which is opened: the liquid spills out and is directed towards a horizontal, constant and still surface. However, when the same experiment is performed with a column of sand grains, the final state has the shape of a bell. The terms that produce this resulting slope, which is no longer horizontal, due to the friction between the particles, is what is referred to as the “Coulomb friction term”.
In addition to the internal friction angles and at the bottom, the mathematicians evaluate other parameters such as the flotability of the submerged material, the topography of the land, the initial direction of the water and its height. Once all these data have been obtained, the mathematicians introduce these into a computer programme and by using animations analyse and visualise the evolution of the submarine avalanches and tsunamis.
The researchers have established the effectiveness of their equations using data from a very well documented tsunami that occurred in Papua New Guinea in 1998. In partnership with geologists from the Spanish Institute of Oceanography (IEO) and by means of a joint project financed by the Junta de Andalucia, the researchers are studying the period during which certain landslides occurred in the past in the vicinity of the Island of Alborán (Almería), and are also evaluating the likelihood of their recurring in the future in the Alborán marine basin.
Scientists from the University of Seville, the University of Malaga, the Escuela Normal Superior in Paris, the University of Savoie, also in France, and from the Seismology Team from the Institute of Physics from the Globe of Paris have all participated in the study.
Greenland ice flow likely to speed up: New data assert glaciers move over sediment, which gets more slippery as it gets wetter
17.08.2017 | Swansea University
Climate change: In their old age, trees still accumulate large quantities of carbon
17.08.2017 | Universität Hamburg
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
18.08.2017 | Life Sciences
18.08.2017 | Physics and Astronomy
18.08.2017 | Materials Sciences