3He dating of rockfalls helps to distinguish between proximal and distal paleo-earthquakes in Christchurch, NZ

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. Continue reading “3He dating of rockfalls helps to distinguish between proximal and distal paleo-earthquakes in Christchurch, NZ”

PhD scholarships in Geophysics at Victoria University of Wellington, NZ

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Good news for students interested in a PhD on tectonics in New Zealand: John Townend announced that several scholarships are available. Deadline for application is 1 July 2014.

PhD students are sought to work on several seismological and geophysical topics within the Institute of Geophysics, School of Geography, Environment, and Earth Sciences, Victoria University of Wellington (VUW). The geophysics group at Victoria University of Wellington has an established track record of research in seismology, tectonics, crustal geophysics, and structural geology. In the most recent Performance-Based Research Fund (PBRF) evaluation, Victoria University of Wellington was ranked first in New Zealand for research excellence and was also ranked first in New Zealand in Earth Sciences.  Continue reading “PhD scholarships in Geophysics at Victoria University of Wellington, NZ”

New earthquake and paleoseismology papers in SRL, J Struc Geol

The latest issue of the Seismological Research Letters (SRL) has at least three papers dealing with topics interesting for paleoseismologists.

Hinzen et al. studied the rotation of objects (e.g., monuments) during the L’Aquila earthquake of 2009. They scanned the rotated objects with a high-res laser scanner, built discrete-element-models from the data and simulated the shaking necessary to cause the deformation. The results help to better estimate earthquake parameters from earthquake archaeological effects (EAEs).

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What’s up? The Friday links (46)

For me the most important geo news this week was the court decision on the L’Aquila trial on Monday. A local court sentenced six scientists and one official for manslaughter to six years in prison – 2 years more than claimed by the prosecutor. Even though the scientists may not have found the best words to describe the earthquake hazard in L’Aquila, the decision is ridiculous in my opinion and caused an outcry throughout the scientific community. Especially the consequences for any risk assessment and public information might be fatal. I am really concerned. In the following I link to some blog posts that I found particularly interesting:

Continue reading “What’s up? The Friday links (46)”

Earthquake series hits Christchurch, NZ, causing liquefaction, landslides

On Monday, 13 June, Christchurch was again rocked by earthquakes that caused damages and left people injured. Three significant events happened within two hours. At 1:00 UTC a mb5.0 event occured, followed by a Mw6.0 at 2:20 UTC and a M4.6 at 2:40 UTC. The strongest event caused instrumental intensities of up to VII close to the city. Update: Geonet reports a magnitude of 6.3. Continue reading “Earthquake series hits Christchurch, NZ, causing liquefaction, landslides”

Why was the Christchurch earthquake so devastating?

A M6.3 earthquake hit Christchurch, New Zealand on 22 February (21 Feb in UTC), leaving at least 75 people dead and hundreds injured or missing. Hundreds of houses were destroyed, including the Christchurch Cathedral, and damages will probably sum up to some billion dollars. On 4 September 2010 (3 Sept in UTC), a M7.0 event struck Christchurch, but then no one was killed. So: what’s the difference between the two events?

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