Dust flux, Vostok ice core

Dust flux, Vostok ice core
Two dimensional phase space reconstruction of dust flux from the Vostok core over the period 186-4 ka using the time derivative method. Dust flux on the x-axis, rate of change is on the y-axis. From Gipp (2001).

Saturday, May 30, 2015

Earthquakes and oil wells in Oklahoma

Further to last week's post on Oklahoma induced earthquakes, I have taken two slides (nos. 8 and 9) from this presentation (pdf), and plotted one atop the other.

In the above figure, the purple circles represent well completions from June 2010 to 2012 (appearing as a semi-transparent layer overtop the other), and the yellow circles represent the epicentres of earthquakes over the same time frame. Not all wells are associated with earthquakes. Most of the earthquakes are located in a few clusters, the three largest of which have been circled.

The reason that not all fracking (and its associated waste water disposal) causes earthquakes is because the local geology has to be predisposed towards producing earthquakes. There have to be natural stresses within the rocks to be released, and it helps if there are pre-existing faults to be activated by these stresses.

The three largest earthquake clusters plotted on a  geological map of Oklahoma (source - pdf). Interesting and complex structures lie at the root of the eastern portion of the map, as well as across the southern portion.

The three major earthquake clusters plotted on a map of fractures in Oklahoma (slide 14 in this document - pdf). I think the projections were different, which was why I couldn't get a very good overlay. But the lower two clusters of earthquakes are definitely in heavily faulted rocks--the northern cluster less so.


  1. Mine and rock oil cycle:


  2. petroleum |pəˈtrōlēəm|

    ORIGIN late Middle English : from medieval Latin, from Latin petra ‘rock’ (from Greek) + Latin oleum ‘oil.’