Global Review of Induced & Triggered Earthquakes Gillian R. Foulger1, Miles Wilson1, Jon Gluyas1, Bruce R. Julian1 & Richard J. Davies2 1Durham University, U.K. 2Newcastle University, U.K.
Environments of induced seismicity Surface operations Adding mass Removing mass Extraction from the subsurface Groundwater extraction Mining Hydrocarbons Geothermal production (heat/fluids) Injection into the subsurface Liquid Gas Explosions Nuclear Chemical Individual cases: Established Speculative Mine quakes, induction established, large mid-crust earthquakes – more speculative association with industrial activity The German Continental Deep Drilling Program (in German Kontinentales Tiefbohrprogramm der Bundesrepublik Deutschland[1]), – KTB McGarr et al. (2002)
Database: 715 cases
Lorca, Spain, 2011 MW 5.1, d = 3 km González et al. (2012) Figure 1 j Location and kinematics of the Lorca earthquake. a, Southwest Spain seismicity (2000–2010), focal mechanisms (1970–2010), long-term GPS velocity (2006–2011, grey) and coseismic vectors (red). Major mapped faults are labelled. b, Lorca city and Alto Guadalentin Basin. IGN mainshock focal mechanisms (black), pre-shock (light grey) and largest aftershock (dark grey), and relocated seismic sequence13. The black stars are damage locations; the red lines are faults11. The contour lines indicate 2 cm yr1 InSAR subsidence due to groundwater pumping14. Blue rectangle: fault surface projection. AMF, Alhama de Murcia Fault. c, Groundwater depth evolution from different data sources (see Supplementary Information). d, InSAR (triangles) and line-of-sight (LOS)-projected GPS ground-surface subsidence at LORC station. Shallow, ~ 3 km depth, Alhama de Murcia Fault González et al. (2012)
Lorca, Spain 9 people killed, 100s injured
Amposta Depleted Oil Field, Spain Injection of cushion gas for storage Oct 2013 > 1,000 earthquakes up to M 4.3 Map of earthquakes compiled by the National Geographic Institute (IGN), used to create seismic hazard maps for Spain 2012. The map draws on historical records as well as recent data. Figure 4: Time sequence of the induced earthquakes. Figure 6: Map of improved earthquake locations. Events larger than M 4 are in red, those with M 3-4 are in blue, and those smaller than M 3 are in green. The EIB will provide a total of EUR 500 million for the project. Cost: ~ $2 billion
Mmax Gas Fields
Oil/Gas Reservoirs, California 1983 M 6.2 Coalinga 1985 M 6.1 Kettleman North Dome 1987 M 6.0 Whittier Narrows All: ~ 10 km deep under producing oil fields uplifting anticlines seismic deformation = required to restore isostatic equilibrium if backflow of water ignored McGarr (1991)
The term “blind thrust” comes up a lot Coalinga 94 injured, felt throughout half the State Whittier Narrows 6 people killed
Oklahoma: Earthquakes & Injection November 2011 M 5.7 Prague event Walsh & Zoback (2015)
All Projects: Mmax vs. Volume
www.inducedearthquakes.org
Last comments Rare phenomenon but predictability poor We need a model for why earthquakes don’t occur Fundamental nature of earthquakes Earthquakes occur whether or not human operations Firing squad problem: Which, of many contributory effects, was “responsible” for an earthquake? Public perception If a large earthquake occurs in a project area, the project may be blamed regardless Potential show-stopper, so needs to be appropriately managed
That’s all folks