USGS likely to upgrade North Texas’ quake risk level

[TexasTowelie]

Until now, North Texas has been one of the least likely places in the country to have an earthquake.

But after the Dallas area suffered a series of more than 120 quakes since 2008, the U.S. Geological Survey is re-evaluating the metroplex’s “seismic hazard” — or the risk of experiencing earthquakes.

This year, for the first time, the USGS will include quakes believed to have been caused by human activity in its National Seismic Hazard Map, which engineers use to write and revise building codes, and which insurers use to set rates.

The map predicts where future earthquakes will occur, how often they will occur and how strongly they will shake the ground.

Read more: http://www.dallasnews.com/news/metro/20150117-usgs-likely-to-upgrade-north-texas-quake-risk-level.ece

[DhhD]

1. Could the subsidence and uplift changes in the ground around North Texas

cause a 6+ earthquake? What parts of North Texas are already sitting on a sink or sink hole?

https://search.yahoo.com/search?p=balcones+fault+map+for+california&fr=ush-mailn_02
Subsidence of rock layers above aquifers.

http://geochange.er.usgs.gov/sw/changes/anthropogenic/subside/


http://www.sciencemag.org/content/345/6204/1587.short
Uplift due to loss of water weight on deep igneous rock layers

https://gsa.confex.com/gsa/2005SC/finalprogram/abstract_83950.htm
Edge pieces of the Balcones Escarpment have fallen in near San Marcos in past geological times.

[DhhD]

2. This map of geologic Cross-Section of North Central Texas show the tipping deposit layers for

what looks like northern Collin (in red), northern Denton and Cook and Grayson Counties. Many of these layers run on down into South Texas (Eagle Ford Formation-shale).
http://www.nhnct.org/geology/csection.html

These layers are tipping southeastward.
http://www.nhnct.org/geology/geohist.html

(Those wonderful Aggies appeared along with all of the other great geologists during very recent times.)

Perhaps someone could provide the January 2015 map(s) showing the changes and additions like aquifers, sinks and uplifts, earthquakes, faults, and more.

[DhhD]

3. Illegal injection into aquifers by Oil Industry.

http://www.dailykos.com/story/2014/10/10/1335729/-3-billion-gallons-of-oil-industry-wastewater-has-been-injected-illegally-into-California-Aquifers

There are several small aquifers in Texas as well as large water fields like the Edwards and Trinity Aquifers.