Real-Time Insights from Passive Seismic Data

PasMon continuously processes data from passive seismic sensor networks and provides:

• Real-time event detection
• Accurate event localization
• Event strength estimation
• 3D visualization of subsurface activity

The system is designed to handle large deployments and is already in operation with more than 4,000 sensors, with scalable CPU/GPU-based performance.

A Different Approach to Event Detection

Traditional microseismic monitoring relies on phase picking—identifying arrival times of seismic waves and iteratively minimizing errors. This approach:

• Requires manual interaction
• Struggles in noisy environments
• Does not scale well to large sensor networks

PasMon replaces this with a stacking-based methodology, which:

• Exploits signal coherency across sensors
• Integrates energy along precomputed travel-time curves
• Provides robust detection even in low signal-to-noise conditions

High-Performance Stacking Technology

At the core of PasMon is an efficient stacking workflow:

• Precomputed travel-time tables for the subsurface
• Real-time stacking of amplitudes across the sensor network
• Identification of event location based on maximum stacked energy

Multiple stacking methods are supported, including:

• Linear stack (fast and efficient)
• Semblance stack
• Weighted semblance

This flexibility allows users to optimize detection performance depending on data quality and operational needs.

Reliable Detection in Noisy Environments

PasMon is specifically designed for challenging conditions:

• Strong noise robustness through coherent stacking
• Signal enhancement using beamforming techniques
• Detection thresholds based on background noise (e.g., STA/LTA methods)

Even weak events that are difficult to identify in raw data can be detected and located with confidence.

Quality Control and Visualization

PasMon provides built-in tools for validation and interpretation:

• Beam visualization for quality control
• Event alignment checks for verification
• Interactive 3D displays of detected events
• Event lists and detailed sensor data views

These tools ensure transparency and reliability in the monitoring workflow.

Integrated in the NORSAR Software Suite

PasMon is fully integrated into the NORSAR Software Suite, enabling seamless workflows with:

• NORSAR 3D – for computation of travel-time tables
• MDesign – for sensor network optimization and detectability analysis
• SeisRoX – for generation of illumination vectors

This integration allows users to move from planning to monitoring within a unified environment.

Designed for the Future

PasMon is built with scalability and extensibility in mind:

• Supports large and dense sensor grids
• Optimized for high-performance computing environments
• DAS (Distributed Acoustic Sensing) support under development