Initially, the volatile radionuclides were thought to be simple, chemical complexes that were generally soluble and thus would be washed out of the soil column, i.e., during rain events. However, if a significant fraction of the highly radioactive Cs is incorporated into more durable particles, then they may persist for longer periods of time. New research outlines a more accurate and consistent way to warn coastal residents when and where tsunami waves are likely to hit.ĮWING: I think that during the past ten years, one of the most important findings is that volatile radionuclides, such as the isotopes of cesium, were actually transported by micro- to nano-scale particles. Science & Technology Q&A: Designing a better local tsunami warning system Ten years after the event, what have scientists learned about the particles released from the Fukushima Daiichi Nuclear Power Plant? Related Story The international scientific community studying earthquake and tsunami hazards from subduction zones is currently planning ambitious experiments involving onshore and offshore instrumentation, which paired with computer modeling, will revolutionize our understanding of these dangerous regions. Scientists now have a much better appreciation for the variability in earthquake (and tsunami) size that can occur in a given region, although the reasons for that variability are still being explored.Ĭomputer simulations of earthquakes have advanced considerably in the past decade, to the point where they can be used to test hypotheses about the role of frictional properties, fluids and other properties and processes on the fault slip behavior. What important insights have scientists gained about earthquakes by studying data from the Tohoku-Oki earthquake and tsunami?ĭUNHAM: The Tohoku-Oki earthquake and tsunami were much larger than had been expected for that part of the Japan Trench subduction zone. Hopefully, other countries that face similar tsunami hazards will invest in offshore sensor networks. Recent offshore earthquakes and tsunamis in Japan have demonstrated that these methods are ready for real-world use, and I anticipate they will start to become part of local tsunami warning systems in Japan within the next few years. (Pressure increases when the wave passes over a sensor.) These methods completely bypass the need to first estimate earthquake properties, and they also work for tsunamis that are caused by non-earthquake sources like underwater landslides. Scientists have new methods for reconstructing the tsunami waves, in real-time, using the seafloor pressure data. Japan has deployed offshore networks of pressure gauges and seismometers connected to each other and back to computers on land by thousands of miles of fiber optic cable. Local tsunami warning systems are still currently based on a two-step workflow: analysis of seismic waves constrain the earthquake location and size, and relations from tsunami simulations are then used to predict tsunami arrival times and wave heights. Science & Technology Rethinking tsunami defenseĬareful engineering of low, plant-covered hills along shorelines can mitigate tsunami risks with less disruption of coastal life and lower costs compared to seawalls.ĭUNHAM: Most tsunamis are caused by offshore earthquakes, like the 2011 Tohoku-Oki earthquake, uplifting the seafloor and the ocean surface so that water begins to flow back toward land in the form of a tsunami. How have local tsunami warning systems changed since the 2011 disaster in Japan? Related Story It might not be coincidental that a lot of that thinking comes from Miyagi Prefecture, which was hard hit by the tsunami. We need to learn a lot more about these types of approaches, but it’s exciting to see progress in that area. There has also been increasing interest in alternative approaches to mitigating tsunami risks such as nature-based or hybrid approaches. SUCKALE: The Tohoku tsunami highlighted that even a highly sophisticated and expensive tsunami mitigation system can fail. What lessons did the damage from Tohoku provide about preparing for tsunamis? Here, Stanford nuclear security expert Rod Ewing and geophysicists Eric Dunham and Jenny Suckale discuss that legacy, as well as how scientists are continuing to discover new details about the disaster. The deadly natural disasters of March 11, 2011, and the catastrophic nuclear meltdown that followed have left a lasting impact on earthquake science, tsunami defense and the politics of nuclear power. More than 19,000 people died and tens of thousands more fled as radiation belched from the world’s worst nuclear accident since Chernobyl.Ī decade later, large swaths of land remain contaminated and emptied of most of their former residents.
0 Comments
Leave a Reply. |