Saturday, October 10, 2020

Drunk on Seismology - Liquefaction Red IPA

The next up in the Drunk on Geology series is Liquefaction Red IPA, the 2016 Geological Society of America specialty label by Left Hand Brewing. Left Hand Brewing was also responsible for the Field Assistant Ale specialty label from the 2013 GSA Annual Meeting. 

Like the Field Assistant Ale, this label is designed by Moxie Sozo and features a couple of geologists in a field vehicle that happened to get inundated within some liquefied sediment. A more complete view of the label can be seen below in the sticker that was given away at the meeting.

The back label

Liquefaction is the process where normally solid sediment can start acting like a liquid when shaken. This can cause multiple things to happen including shaking the ground like Jell-O, or even buildings getting swallowed up within the sediment, like quicksand. Normally, particles in the sediment, are tightly packed. However, during an earthquake, the sediments start to shake and vibrate. As they move about, the spacing between the sediment particles increases. As the spacing increases, the ability for the sediment to act like a liquid increases.

Graphic illustrating how sediment can get liquefied. Image courtesy of Straits Times

The sticker given away at the meeting. You can easily see the whole label here.

The impact that liquefaction can cause was especially notable during the February 6th, 2018 Taiwan earthquake. The earthquake was a magnitude 6.4 and managed to produce severe liquefaction damage, causing entire buildings to get swallowed up into the earth.

Building partially submerged in the ground due to liquefaction of the sediment during the February 6th, 2018 Taiwan earthquake. Image courtesy of The Mercury News.

Another building partially submerged in the ground due to liquefaction of the sediment during the February 6th, 2018 Taiwan earthquake. Image courtesy of The Mercury News.

Water percentage plays a significant role in the degree of liquefaction, as well as the particle size and size/location of the earthquake. High water content and sandy soils are the most susceptible to major liquefaction. In earthquake prone locations, hazard maps are typically created to alert the public of liquefaction potential. 

Liquefaction potential map of Salt Lake City, Utah from the Utah Geological Survey.

Knowing the potential degree of liquefaction can also make the case for stronger building codes, protecting not only the property put the people whom happen to be in those buildings at the time of the earthquake. And although sinking buildings is probably on the extreme end of liquefaction hazards, the biggest impact is just the ground moving like you are sitting on Jell-O during an earthquake. I did a demonstration a while ago on the effects of building on bedrock versus sediment during an earthquake by using Jell-O and Rice Crispy Treats. And although the model is simplified from real life, that makes it no less accurate. Buildings on sediment shake longer and harder than those built on bedrock, causing more damage for similar sized quakes.

The source local for the beer, the 2016 GSA Annual meeting. 

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