Ensuring Safety and Integrity: Seismic Monitoring of LNG Facilities

The liquefied natural gas (LNG) industry is a cornerstone of the global energy market, providing a clean, efficient, and versatile fuel source. As these facilities often lie in seismically active regions, understanding and mitigating the risks posed by earthquakes is crucial for ensuring the safety, integrity, and operational continuity of LNG operations. This blog explores the critical role of seismic monitoring in LNG facilities, focusing on the use of free-field seismic stations and the instrumentation of LNG tanks.

The Importance of Seismic Monitoring in LNG Facilities

LNG facilities encompass liquefaction plants, storage tanks, and regasification terminals, each presenting unique challenges when faced with seismic activity. The catastrophic potential of an earthquake event—ranging from structural damage to catastrophic failure—underscores the need for comprehensive seismic monitoring systems. These systems are designed not only to safeguard the infrastructure and personnel but also to protect the surrounding communities and the environment.

Free-Field Seismic Stations: The First Line of Defense

Free-field seismic stations play a pivotal role in the seismic monitoring framework of LNG facilities. Positioned strategically around the facility, these stations provide real-time data on ground motion and seismic events. By capturing the amplitude, frequency, and duration of seismic waves, these stations offer invaluable insights into the seismic threat landscape, allowing for the timely activation of safety protocols and mitigation measures.

Key Functions of Free-Field Seismic Stations:

  • Early Warning: By detecting seismic waves in real-time, these stations can trigger early warning systems, providing crucial minutes for shutting down operations, thus mitigating risk to both the facility and its personnel.
  • Seismic Hazard Assessment: Continuous monitoring aids in the assessment of seismic hazards, informing both the design of new infrastructure and the retrofitting of existing structures.
  • Data Collection for Engineering Analysis: The data collected serves as a foundational element for engineering analyses, guiding the development of more resilient LNG facility designs.

Instrumentation of LNG Tanks: Enhancing Resilience

The instrumentation of LNG tanks is another critical aspect of a comprehensive seismic monitoring strategy. These instruments, including accelerometers and strain gauges, are installed directly on or within the LNG tanks. They monitor the tanks’ responses to seismic events, providing data that is vital for assessing the structural health and integrity of these critical components.

Benefits of LNG Tank Instrumentation:

  • Structural Health Monitoring: Instrumentation allows for the continuous monitoring of the structural health of LNG tanks, identifying potential issues before they lead to failure.
  • Performance-Based Design Verification: The data collected can verify the effectiveness of seismic design principles, ensuring that the tanks perform as expected during seismic events.
  • Emergency Response and Recovery: In the event of an earthquake, real-time data from tank instrumentation can inform emergency response efforts, facilitating a quicker recovery and return to operation.

Conclusion

The integration of free-field seismic stations and the instrumentation of LNG tanks represents a holistic approach to seismic monitoring in LNG facilities. This dual-layered strategy not only enhances the safety and resilience of LNG infrastructure but also contributes to the sustainability of LNG as a key component of the global energy mix. By investing in advanced seismic monitoring technologies, the LNG industry can navigate the challenges posed by seismic activity, ensuring that it continues to deliver energy safely and reliably to the world.

To learn more about how QuakeLogic can help your LNG facilities to be compatible with regulations and standards by installing seismic sensors and providing earthquake early warning and structural health monitoring, contact us at sales@quakelogic.net and visit us at https://www.quakelogic.net/_lng-facilities-monitoring/lng-monitoring.

Insights into Blast Vibration Monitoring and Infrasound Sensitivity

Blast Vibration Monitoring

Blast vibration monitoring is crucial in industries like mining, construction, and demolition, where explosives are used. It’s important to monitor and control the vibrations caused by blasts to prevent damage to nearby structures and to ensure the safety and comfort of people in the vicinity. The minimum trigger level for blast vibration monitoring can vary depending on several factors, including local regulations, the type of structures near the blasting site, and the project’s specific conditions.

  1. Regulatory Guidelines: Different countries and regions have guidelines for acceptable vibration levels. For example, in the United States, the Bureau of Mines recommends a peak particle velocity (PPV) of 0.5 inches per second for residential structures, but local regulations may set stricter limits.
  2. Type of Structures: Older buildings, historic structures, or buildings with pre-existing damage may require lower vibration limits to prevent further damage.
  3. Distance from Blast: The acceptable vibration level might also depend on the distance of the structure from the blast site. Closer structures may have lower trigger levels.

Infrasound Sensitivity for Long Periods

Infrasound refers to sound waves with frequencies below the lower limit of human audibility (below about 20 Hz). Monitoring infrasound is important for detecting natural phenomena like volcanic eruptions, avalanches, landslides, and tornadoes, and for assessing the impact of human-made sources like wind turbines and industrial activities.

  1. Human Sensitivity: While infrasound below the threshold of hearing is not audible, exposure to high levels of infrasound over long periods can potentially have health impacts, including stress, sleep disturbance, and other physical symptoms.
  2. Monitoring Thresholds: The sensitivity of infrasound monitoring equipment is designed to detect very low frequencies at minimal levels. Modern infrasound sensors can detect pressure changes less than a Pascal, which allows for the monitoring of both natural and anthropogenic infrasound sources over great distances.
  3. Environmental Impact Studies: For assessing the impact of infrasound on humans and wildlife, long-term monitoring is often required. The sensitivity and trigger levels for such monitoring depend on the objectives of the study and the baseline levels of infrasound in the environment.

Both blast vibration monitoring and infrasound sensitivity assessments require a careful approach that considers the specific context of each situation, including regulatory requirements, environmental conditions, and the potential for adverse effects on humans and structures. Continuous monitoring and adherence to established guidelines are key to managing the impacts effectively.

QuakeLogic leads the way in providing state-of-the-art infrasound sensors, dataloggers, and software solutions designed for real-time data analysis. These tools are crucial for professionals seeking to monitor and analyze infrasound with precision and efficiency. To explore the full range of our infrasound monitoring products and understand the powerful capabilities of our software, we invite you to visit our specialized webpage at QuakeLogic Infrasound Sensors.

If you have specific questions or need guidance to select the perfect infrasound monitoring setup for your project, please do not hesitate to get in touch with our expert sales team via email at sales@quakelogic.net. Our dedicated team is committed to providing personalized consultation to ensure that you find solutions that precisely match your monitoring objectives. Reach out today to learn how our technology can elevate your infrasound monitoring capabilities.

Earthquake P- and S-waves, why does their speed matter?

Earthquakes, one of nature’s most formidable phenomena, can cause widespread destruction within seconds. However, advancements in seismology have led to the development of Earthquake Early Warning (EEW) systems, providing precious seconds to minutes of warning before the shaking starts. The key to these warnings lies in the understanding of P-waves and S-waves generated by earthquakes and their speeds.

The Speed of P-waves and S-waves

When an earthquake occurs, it releases energy in the form of seismic waves, primarily P-waves (Primary waves) and S-waves (Secondary waves). P-waves, being the fastest, travel through both solid and liquid layers of the Earth at speeds ranging from about 5 to 7 kilometers per second (km/s) in the Earth’s crust, and 8 to 13 km/s in the mantle. S-waves, on the other hand, only move through solids and are slower, with speeds of about 3 to 4 km/s in the crust and 4.5 to 7.5 km/s in the mantle.

The Importance of Speed Difference

The speed difference between P-waves and S-waves is crucial for Earthquake Early Warning systems. P-waves, although less destructive, reach sensors first, providing a brief window of time before the more damaging S-waves arrive. This time gap can vary depending on the distance from the earthquake’s epicenter. The closer one is to the epicenter, the shorter the warning time, due to the smaller gap between the arrival times of P-waves and S-waves.

Proximity to the Epicenter and Warning Time

For those located very close to the earthquake epicenter, the warning time may be minimal or non-existent. This is because the S-waves, responsible for most of the shaking and damage, follow closely behind the P-waves. In such scenarios, every second of warning can be critical for taking protective actions, such as dropping to the ground, taking cover under a sturdy piece of furniture, and holding on until the shaking stops.

The Blind Zone Challenge

A significant challenge for regional seismic network-based EEW systems is the “blind zone.” This area, typically within 10 to 20 kilometers of the epicenter, may receive little to no warning before shaking starts. The reason is that it takes time for the seismic waves to be detected by the network, processed, and then relayed as a warning to the affected area.

On-site Earthquake Early Warning Systems

To address the blind zone issue, on-site EEW systems have been developed. These systems are installed at individual locations, such as buildings or infrastructure facilities, and can detect P-waves directly, providing immediate local warnings. While they may not offer extensive lead times, they can be especially effective in near-epicenter areas where regional EEW systems struggle to provide timely alerts.

Conclusion

Understanding the dynamics of P-waves and S-waves and their implications for early warning systems is essential in mitigating earthquake risks. While the difference in speed between these waves offers a crucial, albeit brief, window for action, challenges such as the blind zone necessitate innovative solutions like on-site EEW systems. As technology advances, the goal is to extend the warning times and reduce the impact of earthquakes, safeguarding communities and saving lives in the process.