Slow-moving landslides, while not as dramatic as their faster-moving counterparts, can damage infrastructure and cause headaches for the communities they affect. Slow-moving slides are generally associated with rainfall or snowmelt, but a new study in Japan has shown that some of these slides may occur when a certain kind of clay is exposed to cold temperatures. In the January issue of EARTH Magazine, the link between ground temperature and slow slides is explored, including implications for the science of predicting similar landslides around the world.
A year ago this month, a devastating earthquake and tsunami struck northern Japan. Two years and two months earlier, on Jan. 12, 2010, a much smaller earthquake devastated Haiti. Both earthquakes occurred on a weekday and in the afternoon, but there is very little else that is similar about these two events or how the countries have recovered. Both offer reminders about the uncertainties of the effects of disasters.
On June 5, 2012, a massive dock made landfall on Oregon's Agate Beach, just north of Newport. The dock carried with it a host of castaways, including as many as a hundred species of mollusks, anemones, sponges, oysters, crabs, barnacles, worms, sea stars, mussels and sea urchins. A placard on the side written in Japanese revealed that the dock had been unmoored from the Japanese coastal city of Misawa during the catastrophic tsunami on March 11, 2011, bringing with it an essentially intact subtidal community of Asian species to the Pacific Northwest. Although natural rafts have likely been ferrying organisms around the planet since the very beginning of life of Earth, the geologically recent advent of human settlement, culture and infrastructure is fundamentally changing the rafting game, as EARTH explores in our March issue.
The size and type of earthquakes a given fault system may produce remain poorly understood for most major fault systems. Recent superquakes, such as the March 2011 magnitude-9 off Japan and the December 2004 magnitude-9-plus off Sumatra, have been far larger than what most scientists expected those faults to produce. The problem is that current models rely on short historical records, and even shorter instrumental records. Today, scientists are working to rewrite these models based on new paleoseismic and paleotsunami data to create a more comprehensive picture of earthquake activity through time. What they're finding might alarm you.
A team of researchers may have discovered a way to hear earthquakes. Not the noises of rattling windows and crumbling buildings, but the real sounds an earthquake makes deep underground as rock grinds and fails catastrophically. Typical seismic waves have frequencies below the audible range for humans, but the August issue of EARTH shows you where to find the voice of one seismic monster: March 11, 2011, magnitude-9.0 Tohoku earthquake in Japan.
On Feb. 22, a magnitude-6.1 earthquake struck Christchurch, New Zealand, killing nearly 200 people and causing $12 billion in damage. About three weeks later, a massive magnitude-9.0 earthquake struck northern Honshu, Japan. The quake and tsunami killed about 30,000 people and caused an estimated $310 billion in damage. Both events are stark reminders of human vulnerability to natural disasters and provide a harsh reality check: Even technologically advanced countries with modern building codes are not immune from earthquake disasters.