[unav_all] IRIS Webinar on Induced Seismicity, 11/20, 2 PM Eastern

Andy Frassetto andyf at iris.edu
Wed Nov 13 09:36:09 MST 2013


"Induced/Triggered Earthquakes: Examples from Texas" will be presented 
at 2 pm EST (7 pm UTC) on Wednesday, 11/20.

Register to attend: https://www2.gotomeeting.com/register/430431890

You will be emailed a confirmation containing a link for accessing the 
webinar. The presentation and subsequent interactions between the 
speaker, host, and audience are recorded and made available within a few 
days. Access to the webinar archive, along with related materials and 
more information on the series is found here: 
http://www.iris.edu/hq/webinar/

Presenter: Dr. Cliff Frohlich, Associate Director & Senior Research 
Scientist, Institute for Geophysics, University of Texas at Austin

Abstract: The widespread application of hydrofracturing to develop 
petroleum resources has increased the need to dispose of flowback fluids 
in deep injection wells. In several geographic areas this appears to 
have triggered earthquakes in locations where none had been reported 
historically. Texas has had a very active petroleum industry for about a 
century, and at present there are more than 10,000 active disposal wells 
in Texas. Thus Texas serves as a huge natural experiment where we can 
explore how earthquakes are related to both fluid injection and 
petroleum extraction.

The passage between 2009-2012 in Texas of EarthScope's USArray 
Transportable Array seismograph stations provided an opportunity to 
identify and accurately locate earthquakes with magnitudes as small as 
1.5-2.5. Information about locations of wells and monthly volumes of 
water, oil or gas extracted and injected are archived by the Texas 
Railroad Commission and available to the public. With these data we have 
been evaluating the relationship between seismic activity and fluid 
injection and extraction in Texas.

For five different areas in Texas I discuss seismic sequences that 
appear to have been induced or triggered by injection or extraction. In 
two areas there is strong evidence that water injection has triggered 
earthquakes; in two areas there is evidence that the extraction of oil 
and water has triggered earthquakes; and in one area CO2 gas injection 
may have triggered earthquakes.

Although these observations provide strong evidence that injection and 
extraction do induce/trigger earthquakes, there are thousands of active 
wells in Texas that do not trigger seismic activity. The principal 
outstanding unsolved question is why earthquakes are induced/triggered 
near some wells and not at others. Fluid injection for waste disposal 
seems to cause earthquakes more often than fluid extraction. I am aware 
of no instances in Texas where hydrofracturing itself has caused 
earthquakes large enough to be felt at the surface.

Please direct any related inquiries or amusing memes to Andy Frassetto 
(andyf at iris.edu).

System Requirements
PC-based attendees
Required: Windows® 7, 8, Vista, XP or 2003 Server
Macintosh®-based attendees
Required: Mac OS® X 10.5 or newer


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