Induced seismicity (above sensitivity level)
Seismic events attributable to human activities are called induced seismic events, although a distinction should be made between: i) induced seismicity where the stress change caused by the geothermal operation is comparable with the ambient stress acting on a fault, and ii) triggered seismicity where the stress variation induced by geothermal activity is only a small fraction of the natural tectonic stress field (McGarr, 2002). Geothermal development tends to modify the characteristics of a reservoir by withdrawing and injecting hot and/or cold fluid into the underground and has a limited potential to cause felt seismic events. Production and injection rates and pressures, fluid volumes, and injection duration are factors that affect the likelihood and magnitude of induced seismic events.
Informations
- Category: Environmental risks
- Id: F-3
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Phases:
- Drilling / Testing
- Exploitation / Development
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Consequences:
- Economic / Performance / Acceptability
- Health / Safety / Environment
Mitigation
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Prevention:
- Detailed geological and seismotectonic studies to identify faults capable of generating damaging earthquakes
- Operational protocols jointly defined by operators and public regulators (e.g. traffic light system)
- Avoid high re-injection pressure/rate, balanced inj/prod
- Proper design and operation of reinjection wells
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Monitoring:
- Installation of seismic monitoring system
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Corrective measures:
- Stop or reduce operation in accordance with safety protocol
More information is available on the project deliverable (link), or navigate on the online version.
