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Earthquakes and dust clouds

Today’s post of the Landslide Blog about a rockfall caused by a volcanic earthquake reminds me about something that’s in my mind for years already. Could we use dust deposits as a paleoseismological archive? Dust clouds of all sizes, ranging from tiny to huge, can be associated with seismic shaking, especially in arid and mountainous regions. Here I have collected a few videos I found on YouTube. When large amounts of dust settle they should form a distinctive layer recognizable in the sedimentary record, comparable to volcanic ash deposits. Of course they will be harder to be identified, since the material is the local one. I guess this could be done, similar to turbidites in marine paleoseismology. There are papers that describe changes in the aerosol content in the atmosphere after earthquakes, so why not look for them on earth? Dust clouds have been defined as an earthquake environmental effect (EEE) in sense of the ESI2007 scale (Michetti et al., 2007), but I know of no attempt to quantify this effect or to use it for identifying paleoearthquakes. Do you know of any study using terrestrial dust deposits from earthquakes for paleoseismology? There are studies that deal with increased sedimentation rates due to tectonic activity, even including mobilized fine-grained sediments, but I am looking for a dust layer in a lake or something like this.

At least there is the possibility to find paleorockfalls by the dust they produced – which was preserved as a layer in lake sediments (Augenstein, 2007)…

Here’s the videos I found, all of them showing impressive dust clouds.

Dust from earthquake triggered rockfalls and shaking

James Reynolds filmed the ongoing eruption of Paluweh Volcano in Indonesia and especially the growing of the lava dome. On 22 February, 2013, one of the numerous volcanic earthquakes produced very impressive dust clouds and rock falls:

Mw7.2 Laguna Salada (Baja California) earthquake 2010:

The Mw6.7 Northridge Earthquake of 17 January 1994 also produced a significant dust cloud:

Christchurch Earthquake of 23 December 2011 (Mw5.8 – actually, there were at least three M>5.0 EQ on this day and I don’t know which one was caught in the video):

Christchurch, Mw6.2, 23 February 2011:

Dust (mainly) from house collapses:

Apart from dust rising from mountain fronts and hills, there is also a lot of dust coming from collapsed buildings. Naturally, these dust deposits will most likely be removed after the event. Also, they will only be formed if there was a significant settlement with stone (adobe) houses when the quake happened, thus restricting the use as an earthquake indicator for pre-historic events.

Christchurch, Mw6.2, 23 February 2011:

Haiti Mw7.0, 12 January 2010:

 

Also, check out this video from a dust storm, resulting form dried liquefaction sediments, also after the Christchurch earthquake:

 

References:

 

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Christoph Grützner

Christoph Grützner

works at the Department of Earth Sciences, University of Cambridge. He likes Central Asia and the Mediterranean and is looking for ancient earthquakes.

See all posts Christoph Grützner

1 Comment

  • Neta | February 27, 2013|08:33 (UTC)

    You mentioned the Laguna-Salada earthquake, where the differential dust cloud dispersion in this movie was actually used to infer rupture direction! Later on, trenches along the rupture exposed dust accumulation – but not as post-seismic layers. Apparently the amount of airborne particles is not enough to actually form a recognizable layer in the stratigraphy. What was found was that the cracks in the fault zone were filled with very fine sediments, plus a sort of tiny “dust wedge” right at the principle slip surface, and it is hypothesized that the dust washes into the FZ after the first rain event. Didn’t we look at those trenches together last year?

    Bear in mind that this is an arid environment and dust is prevalent not just during earthquakes, but also coming from dessicated lake beds (such as the salada next to it).

    By the way, there’s a planned field-trip to the trenches on the fault during September of 2013. Organized by Tom, of course.

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