When you're investigating complex questions, you've often got to dig deep to find answers. A group of UC Santa Barbara geologists and their colleagues studying tsunamis did exactly that. The team used ground-penetrating radar (GPR) to search for physical evidence of a large tsunami that pounded the Northern California coast near Crescent City some 900 years ago. They discovered that the giant wave removed three to five times more sand than any historical El Niño storm across the Pacific Coast of the United States. The researchers also estimated how far inland the coast eroded. Their findings appear in the journal Marine Geology.
Member Highlight: A Tsunami’s Worth Of Sea Creatures Landed Along The Pacific Coast. Is This A Problem?
They’re a long way from home. Nearly 300 different species of fish, mussels, crabs and various other sea creatures drifted from the shores of Japan to the Pacific Coast of the United States on debris sent across the ocean by a tsunami in 2011.
A team of scientists found something hidden off the coast of Alaska that suggests a significant risk for future tsunamis in the area. The team made the discovery as they were conducting seismic surveys off the Alaskan coast to better understand the regional plate tectonics and subduction. The research, published in Nature Geoscience, provides evidence for an increased tsunami risk in an area previously thought to be low risk for tsunamis. The feature was found by a research team at the Lamont-Doherty Earth Observatory of Columbia University. It is similar to the feature that produced the devastating Tohoku tsunami in 2011 off Japan, which killed approximately 20,000 people and caused three nuclear reactors to melt down.
Benjamin Horton remembers being in Southeast Asia just months after the devastating 2004 Indian Ocean tsunami. “They were still dealing with a disaster,” he says. “The roads were in a terrible state.” But in those days, the formerly niche field of tsunami research had taken on new urgency. Horton, who studies sea levels at Rutgers University and Nanyang Technological University, was just one of dozens of researchers who came in search of answers: Had this happened before? Would it happen again?
Understanding "slow-slip" earthquakes on the seafloor—seismic events that occur over a period of days or weeks—is giving researchers new insights into undersea earthquakes and the subsequent creation of tsunamis. Through an ocean discovery program supported by the National Science Foundation (NSF), scientists are studying the seafloor off the coast of Japan. The region could provide vital clues. Two tectonic plates, the Pacific Plate and the Eurasian Plate, meet there. In this ocean trench zone, the Pacific plate slides beneath the Eurasian plate. Such subduction zones are often associated with large earthquakes.
A new NASA study is challenging a long-held theory that tsunamis form and acquire their energy mostly from vertical movement of the seafloor. An undisputed fact was that most tsunamis result from a massive shifting of the seafloor—usually from the subduction, or sliding, of one tectonic plate under another during an earthquake. Experiments conducted in wave tanks in the 1970s demonstrated that vertical uplift of the tank bottom could generate tsunami-like waves.
Buoys operate as today's state-of-the-art tsunami-detection system. Seismic data can tell officials that an underwater earthquake has occurred, but strategically placed floating sensors often give the key warning if the earthquake has created a potentially devastating series of waves. Even so, warnings are often issued only minutes before a tsunami hits—if at all.
Member Highlight: A New Tsunami-Warning System: Scientists Devise way To Relay Sound Signals Under Water
After successfully testing a long-range underwater communications system that worked under Arctic Ocean ice, an engineering team at Woods Hole Oceanographic Institution (WHOI) adapted it for a very different environment—the tropics—and for a different purpose—to provide warnings of impending tsunamis. While the Arctic sound-signaling system lets researchers communicate with robotic vehicles operating beneath sea ice, the tropical system, tested in 2016 off Indonesia, is designed to relay signals “from an undersea sensor network to shore, where they can be used to estimate the level of the potential tsunami,” said Lee Freitag, the WHOI engineer who led the project.
The tsunami of 2011 is well remembered in Japan. Some towns have recovered, while others struggle to return to a life that once was. The same is true for ecosystems. In a new study in PLOS ONE, Japanese researchers report how the sea life in different coastal regions of Japan struck by the tsunami have flourished or faltered. "We watched in real time an ecosystem recover from a large natural disaster," said Reiji Masuda, who directs the Maizuru Fisheries Research Station at Kyoto University and led the study. "We could observe how species recovered and whether any invading species could thrive."
What may be the largest exposed fault on Earth has been seen and documented by scientists for the first time. The 'Banda Detachment' fault in eastern Indonesia would explain a 7.2km (4.4 mile) deep abyss under the Banda Sea, which until now has remained a mystery to geologists. This area where the fault was found sits in the Ring of Fire, an area in the basin of the Pacific ocean where many volcanic eruptions and earthquakes occur. Sitting under the Banda Sea is the Weber Deep – the deepest point in our planet's ocean that does not sit in a trench.
Seismologists in Japan have tracked, for the first time, a particular type of tiny vibration that wobbled through the Earth from the Atlantic seafloor. It was started by a "weather bomb": the same low-pressure storm, off Greenland, which made UK headlines in late 2014.
Researchers who analyzed a history of tsunamis along the Pacific coast of Japan's Tohoku region have learned that seawalls higher than 5 meters reduce damage and death, while coastal forests also play an important role in protecting the public.