Taxonomy term

In May 2008, a magnitude-7.9 earthquake struck near Wenchuan, China, killing more than 80,000 people in the country’s biggest quake since 1950. Then, in April 2013, the magnitude-6.6 Lushan earthquake hit just 90 kilometers to the south — also within China’s Longmenshan Fault Zone, which separates the Tibetan Plateau to the west from the Sichuan Basin to the east — and caused another 200 deaths. Now, scientists have found that a roughly 60-kilometer segment of the fault zone between the epicenters of the two big temblors could be the next to rupture, although no one knows when or how big it might be.

Mixing contaminated wastewater from hydraulic fracturing, also called hydrofracking or fracking, operations with acid mine drainage (AMD) may sound like an ecological disaster in the making. But according to the authors of a new study, such a toxic brew may actually be a recipe for remediation. And, if some hurdles are cleared, researchers say, it could relieve stress on precious freshwater resources by offering companies drilling for natural gas a cheaper alternative to those resources.

At the beginning of the 19th century, little was understood about Earth’s magnetic field, but interest in its workings had begun to grow, especially in Europe. That the magnetic field exists had long been recognized, and magnetic compasses had aided in navigation for centuries, particularly at sea where fixed landmarks are hard to come by. Not surprisingly, the increased attention emerging around the turn of the century came from naval and shipping interests, which recognized that an accurate understanding of the field’s behavior would be a boon to their fleets.

By this time, the underlying physical explanation for the magnetic field had also become a major source of scientific curiosity. In the preceding two centuries, observers had measured differences in the field’s intensity, inclination and declination — the angle between magnetic and true north — between locations, as well as changes in those properties at the same location, both over varying lengths of time. Others had noted the synchronized occurrence of colorful atmospheric auroras with widespread disturbances in the magnetic field, termed magnetic storms.

It was clear the planet’s magnetic field was an inconstant and complex phenomenon, and many eminent scientists saw it as the next great natural mystery to unravel.