רעידות אדמה באוקלהומה: טקטוניקה ומעשה-אדם Oklahoma earthquakes: Interplay between tectonic and anthropogenic Effexts

סמינר מיוחד - פרופסור זאב רכס, אוניברסיטת אוקלהומה, ארה"ב

It is well known that water injection can raise the pore-pressure within a fault-zone and induce earthquakes, however, the general processes that govern the interactions between an intraplate tectonic setting, anthropogenic activity and increase in seismicity are still not well understood. For example, why most earthquakes in Oklahoma occur in the basement while almost all injection is in the sedimentary cover? What are the effects of injected water on the strength of basement rocks? Do the earthquakes indicate crustal-scale deformation? What are the relationships between the regional in-situ stresses and the local structures?

We are addressing these questions by a collaborative approach that includes geodesy, structural analysis, crustal modeling and rock-mechanics experiments. The relationships between injection, tectonics and seismicity in Oklahoma are viewed through three geodynamic modes: (A) prolonged, large-scale injection that leads to weakening and deformation of the basement; (B) intense, local injection that may activate large faults through direct flow pathways; and (C) large-scale removal/injection of fluids in the sedimentary sequence that redistributes mass and pressure

 


תאריך 24/11/2016 10:30 12:00
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