Seismic Monitoring

• Seismicity

Seismic Activity Rate Monitor

System Overview

The seismic monitoring system consists of three applications:

1. Standard Monitoring App - Basic seismic event monitoring
2. Enhanced Monitoring App - Includes exclusion procedures and additional features
3. Setup App - Configuration and initialisation tool

Both monitoring applications share the same activity rate monitoring functionality, while the enhanced version provides additional user interface elements and exclusion management capabilities.

Activity Rate Monitoring

The system monitors seismic activity on two temporal scales:

• Short-term monitoring - Rapid detection of activity changes
• Medium-term monitoring - Trend analysis over extended periods

Hotspots are automatically identified based on predefined thresholds and displayed in dedicated tables. Users can switch between monitoring modes and interact with hotspots through:

• Visual highlighting of selected areas
• Automated level plan and longsection views
• Alert notifications for new hotspot detection

Configuration Setup

Step 1: Grid Definition

Define the spatial framework for activity assessment by specifying monitored mine areas.

Performance

Tighter grid spacing increases calculation time and reduces reload speed.

Step 2: Reference Rate Configuration

Establish baseline activity rates that account for:

• Location variability - System sensitivity and rock mass response differences
• Data quality - Select consistent datasets spanning several months
• Mining stability - Avoid periods with major operational changes
• Blast filtering - Use time-of-day filters to exclude blasting effects
  • See Time Charts for details

Additional options include applying scaling factors or using constant reference rates across all grid locations.

Step 3: Monitoring Parameters

Configure the following operational parameters:

• Spatial radius around each grid point for activity measurement
• Temporal windows defining short-term and medium-term periods
• Event thresholds specifying minimum event counts for caution/alert triggers

Step 4: Activity Thresholds

Define trigger conditions using either:

Ratio-based Thresholds

• Simple linear function of reference rate
• Direct proportional relationship

Probability-based Thresholds

• Based on Marsan (2003)¹ methodology for detecting seismicity rate changes
• P-value represents probability that current/reference activity ratio exceeds threshold
• Accounts for uncertainty differences between short monitoring periods and long reference periods
• Recommended for statistical rigor (see Marsan and Wyss 2011²)

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All configuration changes must be saved before applying to the monitoring window.

Operational Features

Target Users: Mine control room operators

Primary Functions:

• Real-time seismicity monitoring
• Event alert communication
• Site-specific exclusion area management

Key Capabilities:

• Automatic Data Updates - Eliminates manual reload requirements
• Alert System - Popup notifications for events and system status
• Spatial Visualisation - Exclusion area plotting and mine area isolation
• Navigation Tools - Automatic zoom/rotate to exclusion areas
• Distance Measurement - Calculate distances from survey points to nearest alerts

Training Resources

This video explains the first steps in setting up the seismic monitoring app, specifically regarding event monitors. This should be done prior to setting up activity monitoring.

This video explains how to set up monitor activity rates, within the monitoring app. This should be done after event monitoring has been set up.

This video will describe opening and using the event monitor, once it has been set up in the previous video.

Once the activity rate monitoring window has been set up, this video will explain how to use the function, differentiating between short term and medium term activity hotspots.

The event monitoring function can be set up to show events passing certain thresholds. This video will explain how to set these view settings up.

Footnotes

1. Marsan, D 2003, 'Triggering of seismicity at short timescales following Californian earthquakes', J. Geophys. Res., 108(B5), 2266, doi:10.1029/2002JB001946 ↩

2. Marsan, D & Wyss, M 2011, 'Seismicity rate changes', Community Online Resource for Statistical Seismicity Analysis, doi:10.5078/corssa-25837590 ↩