Rice University Earth scientist Dale Sawyer and colleagues last month reported the discovery of a strong variation in the tectonic stresses in a region of the Pacific Ocean notorious for generating devastating earthquakes and tsunamis in southeastern Japan.
The results came from an eight-week expedition by Sawyer and 15 scientists from six countries at the Nankai Trough, about 100 miles from Kobe, Japan. Using the new scientific drilling vessel "Chikyu," the team drilled deep into a zone responsible for undersea earthquakes that have caused tsunamis and will likely cause more. They collected physical measurements and images using new rugged instruments designed to capture scientific data from deep within a well while it is being drilled.
The Nankai Trough is known as a subduction zone, because it marks the place where one tectonic plate slides beneath another. Tectonic plates are pieces of the Earth's crust, and earthquakes often occur in regions like subduction zones where plates grate and rub against one another. For reasons scientists don't yet understand, plates that should move smoothly relative to each other sometimes become locked. In spite of this, the plates continue moving and stress builds at the points where the plates are locked. The stored energy at these sites is eventually released as large earthquakes, which occur when the locked area breaks and the the plates move past one another very rapidly, creating a devastating tsunami like the one in Sumatra and the Indian Ocean three years ago.
"Earthquakes don't nucleate just anywhere," Sawyer said. "While the slip zone for quakes in this region may be hundreds of kilometers long and tens of kilometers deep, the initiation point of the big quakes is often just about five to six kilometers below the seafloor. We want to know why.”
Sawyer said scientists with the Integrated Ocean Drilling Program (IODP) plan to return to the Nankai Trough aboard the Chikyu each year through 2012, with the ultimate goal of drilling a six-kilometer-deep well to explore the region where the quakes originate. If they succeed, the well will be more than three times deeper than previous wells drilled by scientific drill ships, and it will provide the first direct evidence from this geological region where tsunami-causing quakes originate.
The drilling done by Sawyer and colleagues marked the beginning of this massive project, which IODP has dubbed the Nankai Trough Seismogenic Zone Experiment, or NanTroSEIZE. In addition to the objective of drilling across the plate boundary fault, NanTroSEIZE scientists also hope to sample the rocks and fluids inside the fault, and they want to place instruments inside the fault zone to monitor activity and conditions leading up to the next great earthquake.
"The Chikyu is a brand new ship -- the largest science vessel ever constructed -- and it uses state-of-the-art drilling technology," Sawyer said.
The Chikyu is the first scientific drill ship to incorporate riser drilling technology. Pioneered by the oil industry, a riser system includes an outer casing that surrounds the drill pipe to provide return-circulation of drilling fluid to maintain balanced pressure within the borehole. The technology is necessary for drilling several thousand meters into the Earth.
David Ruth | EurekAlert!
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...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy