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Our colleagues Stéphane Baize and Oona Scotti from the French IRSN finished a report on the 2014 Napa Earthquake: Post-seismic survey report, with special focus on surface faulting. On 24 August 2014, an earthquake of magnitude Mw6 occurred on the West Napa Fault in shallow depth. The quake caused significant damage, an interesting pattern of surface ruptures, and the immediate attention of hundreds of geologists. The primary and secondary effects were mapped only hours after the event, which turned out to be extremely important – a large amount of afterslip was recorded in the following days. The earthquake was not only recorded by a huge seismometer network, but the ground motion was also captured by GPS sensors and InSAR images. The new IRSN report is especially concerned with the surface faulting hazard, since this agency is responsible for the safety of nuclear installations in France.  more

Mediterranean tsunamis, puzzled scientists a year after the South Napa EQ, a new structural geology lab manual, success of brevity and the search of (right) answers. Today is Friday and here are your links!

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Our colleague Tim Dawson from the California Geological Survey (CGS) pointed me to this website, where reports and data on the Napa Earthquake of 24 August, 2014, are collected. There is a new document available for download, the EERI report at the top of the page, which adds some previously unpublished information, especially on the observed afterslip. Tim writes that “afterslip along the central 6-7 km of the rupture is about 35 cm (whereas it was initially only about 20 cm the day of the earthquake).” The afterslip seems to be still ongoing and is monitored with InSAR. more

The M6.0 Napa earthquake came along with some interesting effects. It produced relatively large surface ruptures, but only minor secondary earthquake environmental effects like localized lateral spread, almost no liquefaction and rockfalls, but some hydrological changes. Dozens of geoscientists went out for mapping the earthquake ruptures, supported by InSAR data that precisely show where the ground moved.

Now the Geotechnical Extreme Events Reconnaissance (GEER) Association published a 400-pages report on their findings. The report is available for download here. Make sure to read it, it’s full of data and great photographs of surface ruptures.

Other interesting articles and posts on the Napa quake: more