SIS-1 Infrasound Sensor: Cutting-Edge Infrasound Detection for Civil and Military Applications

The SIS-1 Infrasound Sensor, developed in collaboration with CEA, is a high-performance, low-power sensor designed for a wide range of civil and military applications. This portable sensor provides exceptional infrasound detection capabilities, enabling rapid deployment for diverse monitoring needs.


Key Features and Applications

1. Civil and Military Security Solutions
The SIS-1 sensor is versatile in detecting infrasound events across a broad range of applications.

  • Military Applications: Nuclear explosions, missile launches, and drone detection are among the sensor’s critical uses, enhancing defense and security.
  • Civil Applications: SIS-1 also plays a vital role in natural disaster monitoring, including earthquake and tsunami detection, weather-related phenomena like tornadoes and avalanches, and emerging environmental emissions tracking, such as those from wind farms.

2. Exceptional Detection Range
This sensor is designed to detect infrasound events from frequencies as low as 1 Hz, making it a premier solution in the infrasound sensor market. The SIS-1 supports chainable deployment for extensive coverage and offers easy installation and maintenance, making it ideal for both temporary and permanent installations.

3. Innovative System Composition
The portable SIS-1 system includes:

  • Infrasound Sensor: Core to detecting and monitoring infrasound events.
  • Digitizer and Data Transmission: Ensures accurate data capture and real-time transmission.
  • Power Supply and GPS: Self-contained for autonomous deployment and location tracking.
  • Optional Components: Wind noise reduction systems (WNRS) and a weather station enhance accuracy in varied environmental conditions, maintaining the sensor’s reliability.

Advanced Metrology and Testing Standards

Seismo Wave’s metrology standards underscore the sensor’s quality:

  • Dynamic Infrasound Generator: Calibrates and tests the sensor’s infrasound response.
  • Metrology Room: Offers precise control over temperature, ground vibration, and meteorological conditions, ensuring accuracy.
  • Active Vibration Isolation Tables: Assure minimal interference, critical for accurate low-frequency measurements.

Technical Specifications

The SIS-1 sensor features impressive self-noise characteristics and maintains amplitude and phase accuracy, essential for detecting even the faintest infrasound signals. These specifications make it a top choice for applications requiring precision and reliability.


Whether used for civil applications like earthquake detection or military applications for blast and drone detection, the SIS-1 infrasound sensor stands out for its flexibility, chainable configuration, and adaptability to both routine and high-stakes monitoring scenarios. The SIS-1 is a complete, portable solution for organizations that prioritize early event detection and broad monitoring coverage.

Additional Offerings

At QuakeLogic, we go beyond providing just the SIS-1 infrasound sensor. We also offer:

  • Analog Dataloggers: For accurate and reliable data collection from infrasound sensors.
  • Real-Time Monitoring Software – PulsePro: To enable continuous monitoring and immediate analysis of infrasound data, ensuring quick responses to any detected anomalies.

Special Introductory Offer

We are offering the SIS-1 at a special introductory price, exclusively for our valued customers. We firmly believe that the SIS-1 is poised to meet and surpass your sound detection needs. Take advantage of this limited-time offer and secure your Infrasound Sensor SIS-1 today. Click HERE for the product page.

About QuakeLogic

QuakeLogic is a leading provider of advanced seismic monitoring solutions, offering a range of products and services designed to enhance the accuracy and efficiency of seismic data acquisition and analysis. Our innovative technologies and expert support help organizations worldwide to better understand and mitigate the impacts of seismic events.

Contact Information

Email: sales@quakelogic.net
Phone: +1-916-899-0391
WhatsApp: +1-650-353-8627
Website: www.quakelogic.net

For more information about our products and services, please visit our website at https://quakelogic.net or contact our sales team. We are here to help you with all your seismic monitoring needs.


Thank you for considering our latest product. The SIS-1 infrasound sensor, along with our comprehensive range of analog dataloggers and real-time monitoring software, is designed to provide you with the precision, speed, and reliability required for advanced sound detection. We stand ready to answer any queries or assist you in any way we can.

How to Compute the PGA, PGV, PGD and Response Spectrum of Ground Motion Using Python

When dealing with seismic data, a critical step in understanding the potential impact on structures is analyzing the response to ground motion, often represented as a response spectrum. This Python script by QuakeLogic enables engineers and researchers to compute the response spectrum of seismic time-series data (in .tcl format), plot the results, compute Peak Ground Acceleration (PGA), Peak Ground Velocity (PGV), Peak Ground Displacement (PGD), and save them for further analysis.

In this blog post, we will explain how to use this Python code, its features, and provide an example of how to compute the response spectrum and key seismic parameters (PGA, PGV, PGD) for a given ground motion.

Key Features of the Script

Input and Output:
The script processes input acceleration time-series data stored in .tcl format. The input files should contain acceleration data in units of in/s², which the script converts to g (gravitational acceleration).

Fourier Transform-Based Method:
The response spectrum is calculated using a Fourier transform-based approach, ensuring accuracy across a range of frequencies and damping ratios.

Peak Ground Parameters:
The script computes PGA, PGV, and PGD to offer a complete picture of the seismic intensity. PGA represents the highest acceleration during the event, PGV corresponds to the highest velocity, and PGD reflects the largest displacement.

Plots and Data Files:
The script generates plots of the input acceleration time series, response spectrum, and computed PGA, PGV, and PGD values, saving them in specified directories. It also exports the computed response spectrum and seismic parameters into output files.

Step-by-Step Guide to Use the Script

Installation and Requirements
Before running the script, ensure you have the necessary Python packages installed. Run the following command to install the required libraries:

pip install numpy matplotlib tqdm

Create a Config File
The script reads parameters from a configuration file (config.json). This file specifies the input directory, response spectrum periods, damping ratio, and other critical parameters. Here’s an example of what the config.json should look like:

{
  "sampling_rate": 50,
  "damping_ratio": 0.05,
  "min_period": 0.01,
  "max_period": 5.0,
  "num_periods": 100,
  "input_dir": "input_data/"
}

Run the Script
After preparing the input files (in .tcl format) and the config file, you can run the script using the following command:

python seismic_response_spectrum_analysis.py

The script processes all .tcl files in the specified input directory (input_data/), computes the response spectrum, and outputs the results, including PGA, PGV, and PGD.

Computation of PGA, PGV, and PGD

  1. PGA (Peak Ground Acceleration):
    The highest absolute value of the acceleration time series, representing the strongest shaking the ground experiences.
  2. PGV (Peak Ground Velocity):
    Computed by integrating the acceleration time series over time to derive velocity and extracting the maximum value.
  3. PGD (Peak Ground Displacement):
    Derived by further integrating the velocity time series to calculate displacement, with the peak displacement indicating the largest ground movement.

These values provide critical insights into the severity of ground motion and are vital for structural response analyses.

Generated Outputs

The script generates three key outputs:

  1. Plots:
    The input acceleration time series, response spectrum, and seismic parameters (PGA, PGV, PGD) are plotted and saved as PNG files in the figures/ directory.
  2. Response Spectrum Data:
    The computed response spectrum is saved in .dat format in the output_data/ directory.
  3. Seismic Parameters:
    PGA, PGV, and PGD are computed and saved in an output file for further reference.

How the Code Works

1. Loading Acceleration Data

The script reads acceleration data from .tcl files, which are expected to contain acceleration in in/s². The values are converted to g using a conversion factor.

2. Calculating the Response Spectrum

The script uses the Fourier transform method to compute the response spectrum for each oscillator frequency and damping ratio.

3. Computing PGA, PGV, and PGD

The script integrates the acceleration time series to compute velocity and displacement, identifying the peak values for PGA, PGV, and PGD.

4. Plotting and Saving Results

Once the response spectrum and seismic parameters are calculated, the script plots both the input acceleration time series and the response spectrum. The PGA, PGV, and PGD values are also printed for reference.

Example Code

import os
import glob
import numpy as np
import matplotlib.pyplot as plt
from tqdm import tqdm
import json

IN_S2_TO_G = 386.0886  # Conversion factor: 1 g = 386.0886 in/s²

def calc_sdf_resp(freq, fourier_amp, osc_damping, osc_freq, max_freq_ratio=5., peak_resp_only=False):
    h = (-np.power(osc_freq, 2.) / ((np.power(freq, 2.) - np.power(osc_freq, 2.)) - 2.j * osc_damping * osc_freq * freq))
    n = len(fourier_amp)
    m = max(n, int(max_freq_ratio * osc_freq / freq[1]))
    scale = float(m) / float(n)
    resp = scale * np.fft.irfft(fourier_amp * h, 2 * (m - 1))
    if peak_resp_only:
        return np.abs(resp).max()
    return resp

def calc_spec_accels(time_step, accel_ts, osc_freqs, osc_damping=0.05):
    fourier_amp = np.fft.rfft(accel_ts)
    freq = np.linspace(0, 1. / (2 * time_step), num=fourier_amp.size)
    spec_accels = [calc_sdf_resp(freq, fourier_amp, osc_damping, of, peak_resp_only=True)
                   for of in osc_freqs]
    return np.rec.fromarrays([osc_freqs, spec_accels], names='osc_freq,spec_accel')

def load_acceleration_file(filepath):
    acc_data_in_in_s2 = np.loadtxt(filepath)
    return acc_data_in_in_s2 / IN_S2_TO_G  # Convert from in/s² to g

def compute_pgv(acc, time_step):
    vel = np.cumsum(acc) * time_step
    return np.max(np.abs(vel))

def compute_pgd(vel, time_step):
    disp = np.cumsum(vel) * time_step
    return np.max(np.abs(disp))

def gen_rsa(file_to_use, config, figures_dir):
    data = load_acceleration_file(file_to_use)
    osc_damping = config['damping_ratio']
    osc_freqs = np.logspace(np.log10(1.0 / config['max_period']), np.log10(1.0 / config['min_period']), config['num_periods'])
    time_step = 1.0 / config['sampling_rate']

    pga = np.max(np.abs(data))
    pgv = compute_pgv(data, time_step)
    pgd = compute_pgd(pgv, time_step)

    resp_spec = calc_spec_accels(time_step, data, osc_freqs, osc_damping)

    # Plotting and saving code...
    # (skipped for brevity, similar to original script)

    # Save PGA, PGV, PGD
    with open(f'{figures_dir}/seismic_parameters.txt', 'w') as file:
        file.write(f'PGA: {pga}\nPGV: {pgv}\nPGD: {pgd}\n')

Contact and Versioning

Version: 1.1
Last Update: October 23, 2024

This code was developed by QuakeLogic Inc. to assist with seismic data analysis. For support, contact us at: support@quakelogic.net.

We hope this tool is helpful for your seismic analysis. Let us know if you have any feedback!

Free-Field Seismic Monitoring for LNG Facilities: Ensuring Compliance with FERC Regulations

Liquefied Natural Gas (LNG) facilities are critical components of the global energy infrastructure, but they also present significant safety and environmental challenges. One of the primary concerns for these facilities is seismic activity, which can pose substantial risks to their structural integrity and operational safety. To mitigate these risks, the Federal Energy Regulatory Commission (FERC) has established stringent regulations for seismic monitoring at LNG facilities. This is where QuakeLogic comes in with its advanced Free-Field Seismic Monitoring Solutions, tailored to meet FERC’s regulatory requirements while ensuring the safety and resilience of your LNG operations.


What is Free-Field Seismic Monitoring?

Free-field seismic monitoring refers to the measurement of ground motion away from buildings or structures, typically in open areas near critical infrastructure. These sensors capture the seismic activity that can affect the LNG facility and its surrounding environment, providing crucial data for real-time monitoring, hazard assessment, and compliance reporting. This data is essential for understanding how ground shaking might impact LNG storage tanks, pipelines, and other essential components, ensuring the facility can withstand seismic events without compromising safety.


FERC Regulations and Seismic Monitoring Requirements for LNG Facilities

The Federal Energy Regulatory Commission (FERC) has strict requirements regarding seismic monitoring for LNG facilities, especially in regions with high seismicity. According to FERC regulations, LNG operators must demonstrate that their facilities are designed to withstand earthquake forces and must have systems in place to continuously monitor seismic activity. These regulations include:

  • Installation of Seismic Monitoring Systems: LNG facilities must install seismic instrumentation capable of measuring ground acceleration and other seismic parameters. The data collected must be used for both immediate response and post-event analysis.
  • Real-Time Monitoring and Reporting: The systems must provide real-time monitoring and alerting capabilities to detect seismic events and ensure rapid response protocols are triggered.
  • Data Storage and Analysis: FERC mandates that all seismic data must be stored and available for future review, with the capacity for detailed analysis to assess the impact of seismic events on the facility’s operations.
  • Compliance Reporting: LNG facilities are required to submit periodic reports demonstrating compliance with seismic safety standards, which include detailed information on seismic events and the facility’s structural performance during such events.

Failure to comply with FERC’s seismic regulations can result in significant penalties and operational delays, which is why robust seismic monitoring solutions are crucial for LNG operators.


How QuakeLogic Can Help LNG Facilities Meet FERC Compliance

QuakeLogic offers state-of-the-art free-field seismic monitoring systems specifically designed to meet the unique needs of LNG facilities and ensure full compliance with FERC regulations. Our comprehensive service includes everything from sensor installation to real-time data analysis and compliance reporting, ensuring your facility is always prepared for seismic events. Here’s how we can help:

1. Advanced Seismic Monitoring Equipment

QuakeLogic provides cutting-edge seismic sensors and data loggers designed for free-field installation. These instruments deliver highly accurate and reliable data on ground motion, capable of detecting even the smallest seismic events. Our systems are designed to withstand harsh environmental conditions, ensuring continuous performance in critical LNG facility zones.

2. Real-Time Data Collection and Alerts

Our seismic monitoring systems offer real-time data collection and alerting capabilities. In the event of a seismic event, facility operators will receive immediate notifications, allowing for rapid response to ensure safety and minimize operational disruptions. With 24/7 monitoring, LNG facilities can maintain constant vigilance over seismic risks.

3. Compliance Reporting and Data Analysis

QuakeLogic’s team of seismic experts will assist with the analysis of seismic data, helping you generate detailed reports that meet FERC’s regulatory requirements. We provide regular reporting services, ensuring your facility’s seismic performance is well-documented and ready for review by regulatory bodies. Our reports are designed to be clear and comprehensive, offering valuable insights into seismic hazards and their potential impact on facility operations.

4. Post-Event Analysis and Structural Health Monitoring

In the event of a significant seismic event, QuakeLogic’s systems can provide post-event analysis, including the evaluation of structural health and operational integrity. We offer detailed assessments to determine whether any corrective actions or repairs are necessary, ensuring your LNG facility remains safe and compliant.


Why Choose QuakeLogic for Seismic Monitoring at LNG Facilities?

  • Expertise in Seismic Monitoring: With years of experience providing seismic monitoring solutions for critical infrastructure, QuakeLogic is uniquely positioned to deliver reliable, high-performance systems that meet FERC regulations.
  • Tailored Solutions: We understand the unique needs of LNG facilities and provide customized monitoring solutions designed to address specific site conditions and seismic risks.
  • Turnkey Services: From equipment installation to data analysis and reporting, QuakeLogic offers a full range of services to ensure your facility is compliant with FERC regulations and prepared for any seismic event.
  • Continuous Support: Our team of engineers and seismic experts provides ongoing support, ensuring your monitoring system operates effectively and meets evolving regulatory requirements.

Get Started with QuakeLogic’s Free-Field Seismic Monitoring Services

Stay compliant and protect your LNG facility from seismic risks with QuakeLogic’s comprehensive seismic monitoring solutions. Our systems are designed to meet FERC’s stringent requirements while providing you with the data and insights needed to ensure operational safety and resilience.

Contact QuakeLogic today to learn more about our seismic monitoring services and how we can help your LNG facility stay safe and compliant.


About QuakeLogic

QuakeLogic is a leading provider of advanced earthquake early warning systems, seismic monitoring solutions, offering a range of products and services designed to enhance the accuracy and efficiency of testing, data acquisition, and analysis.

Contact Information:

For more information about our products and services, please visit our website or contact our sales team. We are here to help you with all your testing and monitoring needs.