Lesson 2: Plate Tectonics

Lesson 2: Plate Tectonics

https://www.usu.edu/today/?id=55036

The Wasatch Fault is located along the western edge of the Wasatch Mountains. The fault runs 240 miles through Idaho, and Northern Utah.  It is made up of several smaller segments on average of 25 miles long .  This fault has a vertical motion.  It has lifted the Wasatch Mountains and tilted them slightly to the east. The average rate of uplift is about 1 millimeter per year.

Vertical motion of the Wasatch fault

The fault does not have a slow slip, and will remain locked for hundreds to thousands of years and then will slip 1 to 4 meters rapidly producing strong earthquakes. The Picture below shows the slip of the Wasatch fault.

earthquake.usgs.gov/regional/imw/images/figure1.php

In this  article written by Anthony “Tony” Lowry and Mary-Ann Muffoletto from USU, they talk about how hard it is to predict earthquakes in the continental interiors.  The article goes on to say that only recently have they begun to look at the mantel flow stress and looking deeper into the earth than they have been previously looking at.

“In continental interiors, we know little about the forces that drive the earthquake cycle,” Lowry says. “We rely mostly on the history of past earthquakes to assess hazards. But, because seismic observations cover only a tiny fraction of the time between the largest earthquakes, we can easily miss important parts of the story.”

geology.utah.gov

With new technology and GPS data they have been able to look more closely at 3 factors.  One is variations in gravitational potential energy, another is changes in thickness of the earth’s crust along the Intermountain Belt and the third is changes in strength of the lithosphere.
Lowry says. “We now know we need to be looking for the impetus — that nudge that sets an earthquake system in motion — from flow at depths of 60 to 100 miles, much deeper than where we’d been looking.”