For those interested in Utah's M5.7 #utahearthquake, here's a little history of the region —
From Twitter responses this morning, it seems many are surprised at the event. But Utah is no stranger to quakes. Here's why: (Thread)
From Twitter responses this morning, it seems many are surprised at the event. But Utah is no stranger to quakes. Here's why: (Thread)
Utah sits in what's known as the Basin and Range Province, which is a swath of the west coast from southern Idaho down to Sonora in Mexico. Here, the land is getting pulled apart and like stretching out play-dough, the crust has thinned and cracked. nps.gov/articles/basin…
3. Over many years of extension, stress builds in the system until it breaks. The ripples of energy these breaks send out are what we know as a quake. This cycle has produced the fractured landscape seen today — some blocks of land rise up in mountains, others drop into valleys.
5. Today's M5.7 #utahearthquake struck just west of SLC and seems to be associated w/ the *very* well-known Wasatch fault system. It runs for ~250 miles in a series of cracks known as normal faults. Here's a great @IRIS_EPO explanation for that
6. The human history of the Wasatch fault can be traced back to 1883 when geologist G.K. Gilbert warned of its potential dangers. He pointed out the region's series of cliffs that came from big shifts in the land = big quakes. #utahearthquake. More here: geology.utah.gov/map-pub/survey…
7. The Wasatch fault system is divided into a whole series of segments. In a simplified sense, the longer the section of the system that breaks (or the more segments that break simultaneously) the bigger the earthquake. #utahearthquake
8. *Very* unlikely the whole system would break at once, but geologic investigations hint that sections have previously broken together w/ quakes as large as M 7.5, according to Utah’s Division of Wildlife Resources. #utahearthquake Cool visual here: utahdnr.maps.arcgis.com/apps/Cascade/i…
9. The central part of the Wasatch fault (where today's #utahearthquake struck) is the most active of the region. According to the USGS, this zone produces a M7.0 earthquake every 900-1,300 years (-ish). usgs.gov/natural-hazard…
10. BUT! Never forget that earthquakes are not trains. They don't run on a set timetable. (Tho I suppose that assumes your trains show up on time, and if you live in DC you know that is frequently not the case 😆).
11. There are still plenty of unknowns about the history (and thus future risk) of this region. But in recent years there have been great efforts to study the Wasatch fault from both ground and sky! #utahearthquake Read more about some of these here: usgs.gov/natural-hazard…
12. Back to why the #utahearthquake seemed surprising to some. The issue is our perception of time. We're talking deep geologic time — i.e. the rocks record many thousands of years of our planet's history. Our puny human memories (or even written records) just can't compete.
13. So while Utah is no stranger to big shakes, many of its residents may be! At a magnitude of 5.7, today's #utahearthquake is the largest in the state since 1992, according to the UofU.
https://twitter.com/UofUGG/status/1240270229185286148?s=20
14. Apologies for the delay, I had some other work to turn to. I hope everyone affected by the #utahearthquake is doing okay and staying safe. Expect more aftershocks to come. Here are some tips and many links I assembled for @NatGeo nationalgeographic.com/environment/na…
15. Most #utahearthquake aftershocks will likely be little shakes (M3+), but there's always a small chance some will have more heft. As the situation evolves, the @USGS updates its forecast for what the aftershocks might look like. Take a look here: earthquake.usgs.gov/earthquakes/ev…
CORRECTION: this beautiful mapping comes from The Utah Geological Survey, a division of the Department of Natural Resources. Apologies
@utahgeological @UtahDNR !!
@utahgeological @UtahDNR !!
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