Strong earthquake widely filmed in Chile

A swarm of magnitude ~5-6 earthquakes offshore Chile on April 23 was punctuated two days later by a much larger M6.9 earthquake yesterday evening. While nobody could have specifically predicted the size and timing of this earthquake, it is a terribly unsurprising event, occurring as it did in the midst of this swarm of heightened seismic activity, and in the highly seismically hazardous region of coastal Chile. As has been pointed out …

Who feels earthquakes?

Earthquakes are felt by people somewhere on the globe just about hourly (see this USGS list of felt earthquakes in just the last 24 hours). Some places are particularly prone to them–think Japan, Indonesia, Chile, Italy, California–while some stable parts of the continents will go generations, or even millennia, without anyone there feeling any quaking of the ground. But even in, say, California, where “felt” earthquakes occur daily, most individuals go months …

Here’s what earthquake early warning looks like

When a large earthquake struck the coast of Japan near Fukushima Tuesday morning, people all across the country were alerted nearly immediately–most in advance of significant shaking at their location–by the nation’s sophisticated early warning system. Early warning doesn’t predict the onset of an earthquake, but it does predict the shaking level and time of arrival at locations all around the epicenter once one has begun but before its seismic …

Complex, compound New Zealand earthquake – Part 2: Faulting by Day

Reeling from the massive M7.8 earthquake at midnight, its relentless aftershocks, and the continuing coastal threat of tsunami, New Zealanders awaited daylight on Monday to see the full extent of the destruction. The bizarre seismic records observed overnight had raised confusion and speculation about what faults were to blame for this earthquake. With an epicenter on land but also a several meter tsunami, it was clear that some complicated combination of on- …

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 …

Studying Earthquakes from England

I’m back at it! This blog has suffered a long hiatus for which I could prattle on with a multitude of excuses, but suffice it to say that the shift from U.S. PhD student life to European postdoc life resulted in a pretty vast rearrangement of my day-to-day activities, priorities, schedule, and habits, and I’ve struggled to carve the time for all the things I’m still even more excited to …

Indian slab lurches downward beneath Afghanistan

As I walked into the department this bright brisk morning, coffee cheerily in hand, the live global seismogram display in the atrium caught my eye with an alarming event that had just happened during my bike ride into work. BIG earthquake, somewhere in the vicinity of Central/Southern Asia. Indeed, an earthquake deep (>200 km) beneath the Hindu Kush mountains of Afghanistan had shaken a huge swath of Central and South …

Chile keeps having earthquakes

…and keeps surviving them barely scathed. Chile has this year been rocked by its 3rd Great earthquake this century–its 14th if you include the last. Though the earthquake’s magnitude and the resulting Pacific-wide tsunami earned it headlines, it was a very mild earthquake in the global scheme of seismic impacts. This has a bit to do with the nature of offshore, subduction zone earthquakes, and a LOT to do with …

Wake-up call from the Hayward Fault

During a brief visit to California this week, I, along with a metroregionfull of people, was treated to a rattling little temblor from the Hayward Fault. The quick jolt struck conveniently just before everyone’s morning alarms went off, serving as a wakeup call for the day, and as this season’s broader “wakeup call” reminder that there are big active seams in the crust inching along around and below our cities. …

Views of strong shaking in Nepal and what they teach us

When the ground shook throughout Nepal in April, it was neither predicted nor surprising–the paradox of inevitable but chaotic large earthquakes within well known seismic zones. Though warnings of Nepal’s catasrophic earthquake risk have been sounded for years, and though this magnitude 7.8 and its energetic 7.3 aftershock wrought plenty of death, destruction, and tragedy, scientists are finding themselves somewhat surprised at the apparently rather limited degree of overall damage …