Time-dependent Seismic Hazard Parameters Evaluation with SHAPE MATLAB Package

Seismic processes can be often time dependent at different time scales. Earthquake interactions (e.g., static and dynamic stress changes), anthropogenic activities (e.g., mining, fluid injection, hydrocarbon exploitation) fluid dynamics (e.g., in geothermal fields and volcanic areas) and periodic phenomena (e.g., earth and ocean tides) result to changes in frequency and magnitude distribution of earthquakes. These changes apply in a wide range of time scales from seconds to decades and their evaluation is vital, for seismic hazard assessment in the vicinity of urban and industrial areas. In addition, such estimates can be used in industrial sites to facilitate production optimization, and they also may offer better insights for the underlying physical mechanisms of seismogenesis (e.g., stress transfer, fluid migration pathways and pore pressure, chemical alteration and frictional properties in depth).

SHAPE (Seismic HAzard Parameters Evaluation), is an open source toolbox, based on MATLAB, developed within the SERA (Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe) Project, and is available for use by seismologists and other scientists and engineers in related fields. SHAPE probabilistically estimates the time-dependent, source components of seismic hazard, namely the magnitude distribution and the seismic activity rates, expressed jointly as changes in the exceedance probability of a given magnitude within a predefined period. Alternatively, the changes of the mean return period of a given magnitude is evaluated in moving time windows. Four different magnitude distribution models are included (unbounded and truncated Gutenberg-Richter law and non-parametric kernel). Interactive parameter selection and data filtering routines are also incorporated in the package.

The presentation will cover the capabilities of SHAPE and a demonstration of selected examples from published and ongoing case studies:

• Mining induced seismicity at Rudna Mine, Poland.
• Seismicity triggered by water reservoir impoundment in Song Trahn 2 artificial lake, Vietnam.
• Tidal triggering of microseismicity recorded by an ocean bottom seismometer network in the equatorial mid-Atlantic ridge.

The SHAPE package is developed in two standalone versions (an interactive Graphical User Interface version and a function) as well an online version, integrated in the Thematic Core Service Anthropogenic Hazards (TCS-AH) of the European Plate Observing System (EPOS). The standalone versions can be downloaded for free from a public repository.