Several new papers deal with paleoseismology and active tectonics studies. Wiatr et al. used terrestrial LiDAR to analyse limestone bedrock scarps, Hornblow et al. investigated the Darfield earthquake source in NZ. Sarikaya et al. present new data on offset alluvial fans in Central Turkey; Xu et al. present geological data on two historical seismic events in Tibet. Tectonic morphology is used by Barcelona et al. in NW Argentina. Mathew et al. use remote sensing data to analyze coseismic deformation in China. Ed Garrett and colleagues present data on 1000 years of megathrust quakes in Chile, and Bemis et al. have an interesting article on UAVs and paleoseismology. more
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 There is a new document available for download, the EERI report at the top of the page, which adds some previously unpublished information, especially on the observed afterslip.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 6th INQUA workshop on Active Tectonics, Paleoseismology and Archaeoseismology will be held from 19-24 April, 2015, in Pescina, Fucino Basin, Italy.
We will remember the centenary of the 1915 M7 Fucino earthquake, that was one of the largest and most devastating earthquakes ever occurred in Central Italy.
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The 2011 Christchurch earthquake series had severe consequences and surprised scientists for many reasons. Ground motions were extremely strong despite the relative moderate magnitudes of the quakes (MW 5.3-7.1). The events happened on a system of hitherto unknown faults, some of which are located directly below Christchurch. Earthquake environmental effects (EEE), especially liquefaction, were intense and widespread. It turned out that subsequent quakes reactivated the same feeder dikes of sand blows, showing that saturated sediments are susceptible of liquefaction no matter if they had been liquefied recently (also see the paper of Quigley et al. (2013) on the liquefaction effects). Another stunning lesson was the occurrence of intense rockfall in the vicinity of Christchurch. In a recently published study, Mackey and Quigley (2014) dated rockfall boulders with 3He and show that they allow to estimate the recurrence intervall of local seismic events like the 2011 series. This works is a very interesting way to use EEE for paleo-earthquake studies. more
A couple of new papers on paleoseismology and related fields have recently been published. They deal with active tectonics in China, coseismic uplift in Japan, seismites in Canada, turbidite and lake sediment paleoseismology, earthquake environmental effects in Greece, paleotsunami deposits in India, an earthquake and tsunami in 1531 in Lisbon, tsunamites in Malta, tectonic geomorphology, scaling relationships in the Med, and the 2013 Balochistan earthquake and subsequent tsunami. If you miss recent studies here, drop us a mail. 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
In 2013 the Global Earthquake Model (GEM) –www.globalquakemodel.org – published seven Requests for Proposal covering topics related to the compilation of basic datasets as well as the creation and calculation of an updated probabilistic seismic hazard input model for South America. This initiative is now named the South America Risk Assessment Project (SARA).
Five consortia of South American researchers responded to this request and submitted proposals for the Hazard Component of SARA. These proposals has been recently endorsed by GEM and will constitute different datasets or topic layers for SARA. They include databases on historical and instrumental seismicity, hazardous faults (Quaternary deformation), tectonic geodesy and ground motions. more
On 24 September, 2013, a magnitude 7.7 earthquake occurred in Balochistan, Pakistan. The quake caused intense ground motions and had dramatic consequences – hundreds of people died, and more than 100,000 lost their homes. A secondary effect which caught much attention in the international media was the birth of an island off the Pakistani coast – Zalzala Jazeera or Earthquake Island. Another effect which went almost completely unnoticed was a small tsunami in the Arabian Sea. The tsunami reached wave heights of around 1 m at the Omani coast. In a paper which was recently published in Geology, my colleagues and me document the tsunami effects in Oman. We conclude on a submarine slide off Pakistan as the likely trigger mechanism.
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A good number of interesting papers has been published during the last months, related to active tectonics, paleoseismology and tsunami research. Study sites include Oman, Italy, New Zealand, California, Cascadia, Scotia Sea, and Central Asia. Enjoy reading and tell me, if you miss some publications here!
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Intraplate earthquakes are those that occur far away from plate boundaries in what is often also referred to as slowly deforming regions or stable continental regions (SCR). Seismicity there is comparably low and earthquake recurrence intervals can easily exceed thousands of years for individual faults. However, intraplate quakes do account for a significant number of earthquake fatalities and killed more people than those that happened at plate boundaries during the last 100 years (England & Jackson , 2011). A new book has been published a few days ago, dedicated to summarizing our knowledge of these seismic events. more
