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.
Global seismic hazard maps exist to help societies and decision-makers anticipate and prepare for earthquakes. These maps are supposed to depict the maximum level of ground shaking likely to be produced by an earthquake in a given area. In the past decade, however, ground motions and death tolls in areas struck by earthquakes have far exceeded these maps' projections. Thus, scientists are calling into question the standard methods used to estimate seismic risk, and accepted assumptions and calculations have come under fire.
The debate over hydraulic fracturing has recently focused on the rise in seismicity throughout the primarily stable interior of the United States. These intraplate regions, though not unfamiliar with earthquakes, have been experiencing an increased amount of seismic activity in the last decade. This unusual increase is likely to be caused in part by wastewater disposal practices related to natural gas production. With such a sensitive issue it is important to keep the facts in perspective.
You know you are from Christchurch when you manage to keep your sense of humor through a year of nonstop hardship. This phrase, coined by Christchurch native Bruce Raines, exploded on Facebook and takes on a multitude of equally morose and light-hearted endings. These phrases accurately capture the spirit of the local inhabitants after a series of earthquakes and aftershocks rocked the city, dramatically changing life for all Cantabrians. Homes and historic buildings were leveled, and everyday luxuries such as electricity and plumbing were lost. However, while those of us on the outside watched the disaster unfold for a few days, we were able to safely return to our heated homes and refreshing showers. To this day, many Cantabrians are stuck in a permanent camping mode: boiling water, and using primitive outhouses when available. In the December issue of EARTH magazine, learn more about how the citizens of Christchurch are coping with the disaster, one aftershock at a time."
As EARTH details in its September feature, Thinking Outside the Rocks in the Search for Ancient Earthquakes," modern-day scientists are getting creative in the search for information about past quakes. Read more about how researchers are turning to old newspaper articles and photographs, folklore, petroglyphs, crumpled buildings and toppled monuments - and how learning about past quakes can help seismologists to assess future seismic risk."
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.
About 75 million Americans in 39 states face a significant risk from a strong earthquake. Because of this significant risk, the Congressional Hazards Caucus Coalition will sponsor an earthquake hazards briefing Tuesday, September 20 at 3:00 pm, in room 2325 of the Rayburn House Office Building on Capitol Hill.