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November 16, 2016

Complex, compound New Zealand earthquake – Part 1: Seismology by Night

Just after midnight last Sunday, the whole country of New Zealand was rocked by a massive earthquake at the north end of the South Island. From the outset, this earthquake was more confounding than most, and as more reports and data amass, we’re gaining a picture of a complicated earthquake that stemmed from the failure of several large faults in succession. These successive failures may have resulted from structural linkages …


October 21, 2013

Watch the whole U.S. ripple

Want to see what happens to the ground in the United States when an earthquake snaps the crust elsewhere in the world? The waves ripple outward through the continent oscillating each county and city in turn. This video shows real data from seismometers deployed across the country. Each dot represents a seismometer. Each instrument’s motion is displayed here as alternating red (for upward motion) and blue (for downward motion). Individually …


August 2, 2013

The jiggling Earth, or, what are all those squiggles?

Ever since we first formally recorded one more or less a century and a score ago, the seismogram of an earthquake has become an iconic symbol. Oversimplified and unrealistic ones abound, but natural seismograms of earthquakes are distinctly identifiable. Despite the unique details of every earthquake, seismograms around the world are phenomenally similar. The differences among them are actually what allow seismologists to understand the propagation of earthquakes and the structure …


June 22, 2012

40 years of earthquakes on one seismogram

Want to see the pulse of the Earth? Last year marked the 50th anniversary of the Albuquerque Seismological Laboratory (ASL), a facility in the quiet mountains of New Mexico that is used by the USGS as a hub to maintain both the instruments and data transmission capabilities of the global (GNS) and national (ANSS) seismic networks. The ASL is used to develop new seismograph technology and to test and calibrate instruments …


May 3, 2012

Musings on seismology and earthquake hazard

Phew, I’ve been a neglectful blogger… probably to the benefit of my dissertation research. I’ve got a few interesting posts in the pipeline, so I think I’ll take what time I can to finish them, then set them up so they’re nice and distributed for you to read. In the meantime, you should all check out two cool blogs maintained by earthquake aficionado Arne Christensen, in which he compiles media …


March 12, 2011

Japan quake felt over >2500km radius

One of the many remarkable features about this planet’s largest quakes (like the one that just happened in Japan) is their truly global effect. Be it the tsunami or seismic waves perceptible and imperceptible, most parts of the planet have been touched significantly by the 8.9. Let’s start with perceptible seismic waves, i.e., ones people don’t need sensitive instruments to detect. The elastic energy released by this earthquake was enough …