Page History

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Mmax estimate for reservoir triggered seismicity

Scientific Background

Overall, the analyses of earthquake triggering whatever they are tectonic or anthropogenic seismicity point in time-space scale the key role of the use normalized distance versus absolute distance to relate a trigger to triggered event.  For tectonic earthquakes, there are evidences that the use of the absolute distance captures earthquake- earthquake triggering patterns (as aftershock-mainshock pair) that hide the key properties of the mainshock-aftershock interactions (e.g. Bak et al 2002; Parsons and Velasco, 2009, Tahir et al., 2012, Tahir and Grasso, 2015, de Arcangelis et al 2016).  This supports the link whereby the reservoir influence zone scales with  reservoir (hydrocarbon field or reservoir lake ) size rather than with simple distance to a local “point-source” load, especially in the reservoir near field (e.g., Ibenbrahim et al., 1989,  Grasso et al. 2018). Grasso et al. (2018) suggest that surface reservoir impoundment (onset of production for hydrocarbon field) impacts the upper crust in the same way as earthquake slip changes upper crust stresses. The surface reservoir load modifies the state of stress, specifically the vertical stress and the effective stresses, through pore-pressure changes, in an area that scales with L_r, the reservoir length (Grasso et al.2018). The same way goes for conventional hydrocarbon reservoir depletion (e.g. Segall et al. 1994). 

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When using the reservoir size,  (Lr) the reservoir length is converted to M using M(Lr) relationship for earthquake (e.g. Wells Coppersmith 1994). It provides an Mmax =M(Lr) estimate that is very conservative value as rarely (less than 5%) overpassed. A second estimated is the average (<Mmax>) Mmax estimate for a given Lr reservoir, that corresponds to <Mmax> = M(Lr) – 2 (e.g. Grasso et al. 2018a,b)

Bak, P., Christensen, K., Danon, L., & Scanlon, T. (2002). Unified scaling law for earthquakes. Physical Review Letters, 88(17), 178501.

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Wells, D. L., & Coppersmith, K. J. (1994). New empirical relationships among magnitude, rupture length, rupture width, rupture area, and surface displacement. BSSA 1994

How to use the application

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Figure 1. Input window of estimate of maximum possible magnitude from induced deformation.

The user is now requested to fill the fields shown above:

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     3) Input data – the user should choose one of the data: water reservoir or hydrocarbon reservoir. Both data come from HiQuake: The human-induced earthquake database. (2016) The data can be found online https://inducedearthquakes.org/

 After defining the aforementioned parameters, the user shall click on the "Run" button and the calculations are performed. The Status changes from 'CREATED' through 'RUNNING' and finally 'FINISHED' and the output is created and plotted in the main window just below "RUN" button.

Figure 3 describes the outputs, possible Mmax estimation for water reservoir case.

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 Note user gets the same type of 2 output plots for hydrocarbon reservoir case.