Induced seismicity

What Is Induced Seismicity?

Induced seismicity refers to earthquakes and tremors that are caused by human activities that alter the stresses and strains on Earth's crust. Unlike natural seismic events, induced seismicity directly results from human intervention, often related to industrial processes. Understanding and managing the risks associated with induced seismicity falls under the broader umbrella of Environmental Risk Management, as these events can have significant Economic Impact on communities and industries. The increasing frequency of such events in certain regions has brought induced seismicity to the forefront of discussions concerning Externalities of industrial operations, particularly within the energy sector.

History and Origin

The concept that human activities could trigger earthquakes gained scientific recognition in the mid-20th century. One of the earliest and most notable instances was observed in the 1960s near Denver, Colorado, where fluid waste-disposal operations at the Rocky Mountain Arsenal were linked to increased seismic activity. This discovery, studied by the U.S. Geological Survey (USGS), provided early evidence that injecting fluids into the subsurface could alter fault stability and induce earthquakes.¹⁰ While knowledge of induced seismicity continued to develop, it expanded dramatically in the early 2010s, primarily due to a significant increase in earthquakes in the central United States.⁹ This surge has been widely attributed to the deep injection of large volumes of wastewater, a byproduct of oil and gas production, into disposal wells.⁸

Key Takeaways

• Induced seismicity refers to earthquakes caused by human activities, predominantly the deep injection of wastewater from oil and gas production.
• These events can cause damage to infrastructure and property, leading to significant economic and social consequences.
• Regulatory bodies and industry often implement measures such as volume restrictions and well closures to mitigate the risk of induced seismicity.
• Understanding the geological context, including the presence of faults, is crucial for assessing the potential for induced seismicity.
• Ongoing research aims to improve the prediction and management of human-triggered seismic events.

Interpreting Induced Seismicity

Interpreting induced seismicity involves analyzing seismic data in conjunction with industrial activity data to determine a causal link. When an area experiences a sudden increase in earthquake frequency or magnitude, researchers investigate whether nearby human operations, such as fluid injection or extraction, correlate with the seismic events. This process helps differentiate induced events from natural tectonic earthquakes and informs policy responses. The severity of induced seismicity is often evaluated by its potential for ground shaking and the resulting impact on human populations and built environments. Effective Regulation and adaptive Energy Policy are critical in mitigating these impacts, particularly in regions prone to such events.

Hypothetical Example

Consider "Permian Energy Inc.," an oil and gas company operating in a fictional geological basin known for its prolific hydrocarbon reserves. As part of its operations, Permian Energy Inc. utilizes deep injection wells to dispose of large volumes of wastewater, a common byproduct of oil and gas extraction. Over several months, residents in nearby rural communities begin reporting unusual ground tremors, followed by minor damage to homes, such as hairline cracks in foundations and walls, affecting their Property Value.

Local seismological observatories, collaborating with state geological surveys, begin to notice a clustering of small to moderate earthquakes directly correlating with the high-volume injection activities of Permian Energy Inc. Initial analysis indicates that the injected fluids are increasing pore pressure along a previously dormant fault line. The increased pressure is reducing the effective stress holding the fault in place, allowing it to slip and generate earthquakes. This scenario exemplifies induced seismicity, where the company's operational activities have a direct and measurable effect on local Infrastructure and the environment. As a result, the company faces scrutiny and potential regulatory action, including directives to reduce injection volumes or cease operations in certain areas.

Practical Applications

Induced seismicity has direct implications across several sectors, influencing investment decisions, market dynamics, and regulatory frameworks. In the energy industry, particularly for companies involved in hydraulic fracturing and wastewater disposal, understanding and managing induced seismicity risks are crucial for operational continuity and social license. Regulatory bodies in affected regions, such as Texas, have imposed restrictions on wastewater disposal volumes and even ordered the shutdown of wells in response to seismic events, directly impacting Capital Expenditures and operational costs for producers.⁷

Furthermore, the occurrence of induced seismicity can affect regional Market Volatility in housing and commercial real estate due to concerns about property damage and safety. It also has a profound impact on Insurance markets, as insurers may adjust premiums or coverage in high-risk areas. From a broader perspective, induced seismicity highlights the interconnectedness of industrial activity and environmental well-being, influencing discussions around Environmental, Social, and Governance (ESG) investment criteria and sustainable Asset Management practices.

Limitations and Criticisms

Despite advancements in understanding, predicting and precisely mitigating induced seismicity remains a complex challenge. A primary limitation is the inherent uncertainty in subsurface geology; even with extensive mapping, not all pre-existing fault lines are known or their susceptibility to fluid injection fully understood. This can make it difficult to anticipate whether a specific injection activity will trigger an earthquake large enough to cause concern.⁶

Furthermore, while the majority of studies have focused on establishing a retrospective association between seismic events and oil and gas activities, forward-looking predictive models are still developing.⁵ Critics point out that the economic and social costs of induced seismicity, including damage to homes and infrastructure, present a significant Liability for operators and a burden on affected communities. For instance, the economic disruptions and repair costs can be substantial, as seen in areas like West Texas where damaging earthquakes linked to oil and gas operations have prompted disaster declarations.⁴ The potential for long-term Economic Impact due to these events adds to the complexities of risk assessment in regions with active fluid injection programs.

Induced Seismicity vs. Natural Earthquakes

Induced seismicity and natural earthquakes both result from the sudden release of energy along faults within the Earth's crust, producing ground shaking. However, their fundamental causes differ significantly. Natural earthquakes, also known as tectonic earthquakes, are caused by geological forces stemming from the movement of Earth's tectonic plates, which build up stress over long periods until faults rupture. These events typically occur along well-defined plate boundaries or pre-existing fault zones due to the continuous motion of the Earth's lithosphere.

In contrast, induced seismicity is directly attributable to human activities that alter the stress state of the crust, often through changes in pore pressure or stress fields. The most common cause is the deep underground injection of fluids, such as wastewater from oil and gas production, which lubricates faults and makes them more prone to slipping. Other activities, like geothermal energy production, carbon capture and storage, and even reservoir impoundment (filling large dams), can also induce seismic events. While natural earthquakes can reach very high magnitudes, most induced seismic events are of low magnitude, though some sites can experience larger quakes.

FAQs

What human activities primarily cause induced seismicity?

The most significant human activity linked to induced seismicity is the deep underground injection of wastewater, a byproduct of oil and gas extraction processes like hydraulic fracturing.³ Other activities, such as the filling of large reservoirs behind dams, geothermal energy production, and carbon sequestration, can also contribute.

What are the potential consequences of induced seismicity?

The consequences of induced seismicity can include property damage, such as cracked foundations and walls, disruption to local Infrastructure, and potential risks to public safety. These events can also lead to increased Insurance costs and regulatory actions that impact industrial operations.

Can induced seismicity be predicted or prevented?

Predicting specific induced earthquakes with certainty is currently not possible, but scientists can identify areas with a higher likelihood of induced seismicity based on geological conditions and injection volumes. Prevention and mitigation efforts often involve regulatory measures, such as limiting injection volumes or pressures, monitoring seismic activity, and, in some cases, shutting down wells. Effective Risk Management strategies are crucial for industries operating in susceptible regions.

How does induced seismicity affect the financial industry?

Induced seismicity impacts the financial industry through various channels. It can affect the Property Value of homes and commercial buildings in affected areas, influence Insurance markets, and create Liability concerns for companies whose operations are linked to seismic events. Investors may also consider these risks when evaluating companies, particularly in the energy sector, as part of their Environmental, Social, and Governance (ESG) analysis.

Are all earthquakes in areas with oil and gas activity considered induced?

No, not all earthquakes in areas with oil and gas activity are necessarily induced. Natural tectonic activity can also occur in these regions. However, a significant increase in earthquake frequency or a correlation with specific industrial operations, particularly fluid injection, often points to induced seismicity as the cause.² The U.S. Geological Survey (USGS) conducts research to distinguish between natural and human-induced earthquakes.¹