Galperin vs Orthogonal Seismometer Configurations: What’s the Difference and Why It Matters?

In seismic monitoring, triaxial seismometers are essential tools that capture ground motion in three dimensions. But not all triaxial sensors are designed the same way. Two dominant configurations exist: the orthogonal layout and the Galperin symmetric design. Understanding the difference between them is key when deciding how to choose a broadband seismometer or designing your seismic network.

Orthogonal Configuration: The Traditional Layout

Orthogonal seismometers use three sensing elements aligned at right angles:

  • X-axis (East-West)
  • Y-axis (North-South)
  • Z-axis (Vertical)

This configuration provides direct and intuitive measurements of ground motion along geographic axes. It is commonly found in strong-motion sensors and legacy seismic stations.

Pros:

  • Simple and direct mapping to geographic directions
  • Standard format for data processing
  • Useful in structural monitoring when orientation is controlled

Cons:

  • Requires precise alignment to true North and level installation
  • Uneven horizontal sensitivity
  • Prone to increased cross-axis coupling due to asymmetry

Galperin Configuration: The Modern Symmetric Design

First introduced by Evgeny Galperin, this configuration uses three identical sensors, each spaced 120° apart and tilted equally from vertical (typically ~35.26°). Rather than directly measuring along X, Y, and Z, these sensors capture intermediate components. Standard vertical and horizontal motion is then reconstructed through a simple mathematical transformation.

Galperin geometry forms the basis of modern broadband seismometers, including all broadband seismometers offered by QuakeLogic.

Pros:

  • Isotropic azimuthal sensitivity for uniform horizontal response
  • Mechanically balanced and compact design
  • Easier installation — no need for precise geographic orientation
  • Ideal for low-noise, high-fidelity broadband recording
  • Often includes self-leveling mechanisms

Cons:

  • Requires post-processing to derive standard components (Z, N, E)
  • May be unfamiliar to users expecting direct XYZ outputs

Coordinate Transformation in Galperin Systems

The raw sensor outputs (V1, V2, V3) from a Galperin layout are converted into vertical (Z) and orthogonal horizontal (X, Y or N, E) components through a transformation matrix. The result is functionally identical to orthogonal output — but with superior mechanical and dynamic performance.

To obtain standard seismic components — vertical (Z), north (N), and east (E) — from a Galperin-configured broadband seismometer, a mathematical transformation is applied to the raw outputs of the three equally tilted sensors.

Galperin sensors are mounted 120° apart in azimuth and tilted at approximately 35.26° from vertical. This symmetric geometry ensures equal sensitivity in all horizontal directions, making it ideal for high-fidelity broadband seismic recording.

The transformation to orthogonal components is handled by a fixed matrix derived from the Galperin geometry. Here’s a practical example in Python that demonstrates how to convert the raw Galperin outputs (V1, V2, V3) into Z, N, and E components:

import numpy as np

def galperin_to_orthogonal(V1, V2, V3):
    """
    Transforms Galperin outputs (V1, V2, V3) into orthogonal components (Z, N, E).
    
    Assumes Galperin sensors are tilted 35.26 degrees from vertical and 120 degrees apart in azimuth.
    """

    # Galperin angle in degrees and radians
    alpha_deg = 35.2643897  # approximately arccos(1/sqrt(3))
    alpha_rad = np.radians(alpha_deg)

    # Transformation matrix based on Galperin geometry
    # Source: Galperin 1985; commonly used form
    T = np.array([
        [np.cos(alpha_rad), np.cos(alpha_rad), np.cos(alpha_rad)],  # Z (vertical)
        [np.sin(alpha_rad), -0.5 * np.sin(alpha_rad), -0.5 * np.sin(alpha_rad)],  # N (North)
        [0, np.sqrt(3)/2 * np.sin(alpha_rad), -np.sqrt(3)/2 * np.sin(alpha_rad)]  # E (East)
    ])

    # Stack Galperin outputs into column vector
    V = np.array([V1, V2, V3])

    # Perform transformation
    Z, N, E = T @ V

    return Z, N, E

# Example usage
V1, V2, V3 = 0.1, 0.2, 0.15  # Example raw sensor outputs
Z, N, E = galperin_to_orthogonal(V1, V2, V3)

print("Vertical (Z):", Z)
print("North (N):", N)
print("East (E):", E)

This code is useful for researchers, engineers, or software developers integrating Galperin seismometers into their own data acquisition systems or post-processing pipelines.

Why Galperin Excels in Broadband Performance

Galperin-configured sensors offer lower cross-axis sensitivity, reduced internal noise, and azimuthal symmetry. This makes them particularly suited for high-precision seismological research.

Optimizing Your Network Design

Because Galperin-based instruments don’t require precise geographic orientation, they simplify field deployments and reduce installation error. This is especially helpful in large-scale projects and remote installations.

✅ QuakeLogic’s Seismometer Solution

At QuakeLogic, we exclusively offer Galperin-type broadband seismometers, engineered for superior sensitivity, symmetrical mechanical design, and fast, easy deployment. Our systems are:

  • Fully turnkey, with no licensing or calibration fees
  • Designed for broadband performance with low self-noise
  • Delivered with user-friendly software and optional remote monitoring tools
  • Compatible with standard seismic analysis workflows

Whether you’re deploying a temporary station or building out a national seismic network, Galperin configuration delivers the performance you need with the reliability you trust.

📞 Contact Us

Ready to upgrade your monitoring system? Reach out to our team at sales@quakelogic.net or browse our product line at products.quakelogic.net to explore QuakeLogic’s advanced broadband solutions.

Tired of Low-Frequency Noise Harassment? QuakeLogic Has the Solution.

If you’ve ever been bothered by a deep, persistent rumble in your home—something you feel more than hear—you’re not alone. Across the country, families are reporting a disturbing rise in low-frequency noise harassment, often caused intentionally by neighbors using subwoofers, industrial equipment, or other infrasound sources. The effects can be both physical and psychological: headaches, stress, loss of sleep, and a deep sense of unease in your own space.

This isn’t just a nuisance. It’s harassment. And it’s hard to prove—until now.


Why Low-Frequency Noise Is Dangerous to Your Health

Infrasound (low-frequency sound below 20 Hz) is often imperceptible to the human ear—but your body still feels it, and the long-term exposure can have serious consequences:

🧠 Headaches & Migraines – Constant infrasound exposure can trigger tension and pain, even when you’re unaware of the source.
🛌 Sleep Disturbance & Fatigue – These low-frequency vibrations can disrupt deep sleep cycles, leaving you exhausted, irritable, and less focused.
💓 Increased Stress & Anxiety – The body interprets infrasound as a warning signal, activating your stress response and leading to chronic anxiety.
🎯 Cognitive Impairment – Extended exposure has been linked to reduced concentration, memory issues, and mental fog.
🩺 Cardiovascular Strain – Some studies suggest that long-term infrasound exposure can increase blood pressure and heart rate.

This is more than an annoyance—it’s a silent health threat. If you’re experiencing symptoms without a clear cause, infrasound may be the hidden culprit.


The Power of Infrasound Detection at Your Fingertips

At QuakeLogic, we believe everyone has the right to peace in their own home. That’s why we proudly offer the Raspberry Boom Seismo-Acoustic Monitor, a powerful, affordable tool designed to detect and pinpoint infrasound disturbances.

Our infrasound sensor is built with advanced technology capable of detecting low-frequency sound waves that conventional microphones can’t capture. These invisible sound waves can penetrate walls, travel long distances, and cause real harm—but Raspberry Boom gives you the power to fight back.

With it, you can:

Detect and log infrasound events in real-time
Identify patterns and timing of the harassment
Pinpoint the source with location tracking when used in a small sensor network
Create compelling evidence for police reports or legal action
Reclaim peace in your home and protect your loved ones


Why Raspberry Boom Is the Best Choice

  • Plug & Play Simplicity – No technical background? No problem. Raspberry Boom comes with free, user-friendly software to get you started immediately.
  • Live Monitoring and History Logs – Stay aware of what’s happening and when.
  • Affordable Protection – Priced with families in mind, this powerful tool includes free shipping and is available right now on our website.
  • Trusted by Scientists and Homeowners – Raspberry Boom is part of a global infrasound network trusted by researchers worldwide.

A Smart Investment in Peace of Mind

Low-frequency noise harassment is real, and it’s affecting more people every day. Whether you suspect a neighbor is deliberately targeting you, or you’re just unsure of what’s causing that strange vibration in your home, Raspberry Boom gives you the power to know, prove, and act.

🛒 Buy now and protect your peace:
👉 https://products.quakelogic.net/product/rsboom-seismo-acoustic-monitor/

🔒 Protect your family.
🧘‍♀️ Regain your peace.
⚖️ Build your case with real, scientific data.

Seeing (and hearing) is believing. Don’t let invisible noise take over your life—let QuakeLogic help you fight back.

Why does Japan frequently experience earthquakes?

Japan, a country renowned for its rich cultural heritage and technological advancements, also faces a unique natural challenge: it is one of the most earthquake-prone regions in the world. The reason behind this frequent seismic activity is deeply rooted in the country’s geographical positioning.

Situated on the Pacific Ring of Fire

Japan is located atop the Pacific Ring of Fire, a zone teeming with tectonic activity. This region is where four major tectonic plates – the Pacific, North American, Eurasian, and Filipino – converge. These colossal rock formations serve as the unstable foundation upon which Japan rests. The constant shifting and colliding of these plates lead to frequent earthquakes, some of which have the potential to trigger devastating tsunamis, especially if the disturbances occur underwater.

Japan’s Ingenious Adaptation

In response to this volatile environment, Japan has become a world leader in earthquake preparedness and building resilience. Homes, hospitals, schools, and other critical infrastructure in Japan are constructed to endure the tremors, adhering to strict regulations regarding design and materials. Earthquake drills are a regular practice in schools and workplaces, reflecting the nation’s commitment to preparedness. While earthquakes are inherently unpredictable, Japan’s proactive stance on disaster readiness is commendable and consistent.

The Contrast: Japan vs. Other Earthquake-Prone Regions

A stark contrast to Japan’s preparedness was observed in last year’s tragedy in Turkey, where a 7.8 magnitude earthquake led to catastrophic destruction and loss of life. In comparison, Japan’s resilience was evident during a recent 7.6 magnitude earthquake, which resulted in minimal damage. This disparity highlights the effectiveness of Japan’s disaster readiness and building standards. However, challenges like tsunamis remain, posing significant threats that require continuous vigilance and innovation.

The Role of Early Warning Systems and Structural Health Monitoring

In light of Japan’s seismic vulnerability, the importance of earthquake early warning systems cannot be overstated. These systems provide crucial seconds to minutes of advance notice, enabling people to seek safety and shut down critical operations, thereby mitigating the impact.

Similarly, structural health monitoring is vital for assessing the integrity of buildings and infrastructure. Continuous monitoring can detect potential weaknesses or damages early, allowing for timely repairs and reinforcement, which is essential in earthquake-prone regions.

QuakeLogic: A Pioneer in Earthquake Preparedness

In the realm of earthquake early warning and structural health monitoring, QuakeLogic stands out with nearly two decades of experience. QuakeLogic’s expertise in these fields is not just about technology; it’s about saving lives, protecting properties, and enhancing resilience against nature’s fury.

As Japan continues to navigate its challenging geological landscape, the lessons learned and technologies developed there are invaluable to the rest of the world. QuakeLogic remains committed to contributing to this field, providing state-of-the-art solutions for disaster readiness and structural integrity.


Connect with us for more insights on earthquake preparedness and innovative solutions. Follow our journey as we continue to support earthquake-prone regions like Japan in their quest for safety and resilience.