NEW Seismic Activity Rate Monitor

The seismic monitoring applications have been modified in the latest root update. There are now two seismic monitoring applications and a third app for setup. The two different monitoring apps are required because not all sites wanted to use exclusion procedures. The monitoring app with exclusions has a different user interface structure and a few extra features.

A new window has been added to monitor activity rate so that both monitoring apps have windows to monitor events and to monitor activity rate. The activity rate monitor is the same in both apps. The Setup app is used to initialise and modify all of these monitoring windows. New training videos for seismic monitoring have been uploaded.

https://mxrap.com/training-videos/monitoring-app/

 

 

Activity rate is monitored on a short-term and medium-term basis. Short and medium-term hotpots are listed in two tables based on pre-defined activity rate thresholds and users can switch between short and medium-term monitoring modes. Each hotspot can be highlighted and there are automatic controls for level plan and longsection views. An alert popup message is triggered when a new hotspot has been detected when there were no hotspots beforehand.

 

 

The following steps are required to setup the activity rate monitor.

1.  Define Grid. Activity rate is assessed based on a grid. Specify the areas in your mine that you want to operate the activity monitor. Note that tighter grid spacings will slow down the calculations and reload speed.

2.  Reference Rate. The reference rate is the basis for the activity monitor thresholds. The reference rate may vary by location since the “normal” activity rate for a particular area will depend on the system sensitivity and rock mass response. Try and select at least a few months of events with consistent data quality and where there has been no major change in mining conditions. Use the time-of-day filter to remove the effects of blasting if desired (see diurnal chart). You can also add an extra factor to the reference activity rate or simply use a constant reference rate across all grid locations.

3.  Monitoring Parameters. You need to specify a radius around each grid point to measure the activity rate and define the time period that constitutes short-term and medium-term activity rate monitoring. You can also specify a minimum number of events to trigger an activity rate caution or alert. You probably don’t want to trigger an alert whenever any event happens.

4.  Activity Thresholds. This is where to define what activity rates will trigger a caution or an alert. You can either specify activity thresholds based on a probability or based on a ratio. Ratio-based activity thresholds are a simple linear function of the reference rate. Probability thresholds are based on the work of Marsan (2003) on detecting seismicity rate changes between two time periods. The P-value refers to the probability that the ratio of the current activity rate to the reference activity rate is greater than the activity ratio (r). If the activity ratio is one, the P-value is simply the probability that the current rate is greater than the reference rate. The probability-based thresholds account for the different uncertainty introduced by using a very short time period (e.g. 30 mins) to assess the activity rate compared to a reference rate measured over a much longer period (e.g. 6 months). For further reading I recommend the Marsan and Wyss (2011) document linked below.

Once you have reviewed all the parameters and thresholds, the settings must be saved before they will be applied to the activity rate monitoring window.

Marsan, D 2003, ‘Triggering of seismicity at short timescales following Californian earthquakes’, J. Geophys. Res., 108(B5), 2266, doi:10.1029/2002JB001946. Available at: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2002JB001946 

Marsan, D & Wyss, M 2011, ‘Seismicity rate changes’, Community Online Resource for Statistical Seismicity Analysis, doi:10.5078/corssa-25837590. Available at: http://www.corssa.org/export/sites/corssa/.galleries/articles-pdf/Marsan-Wyss-2011-CORSSA-Rate-changes.pdf

New Monitoring/Control Room App

We previously created a Basic Seismic Monitoring app but it didn’t get widely used. We’ve taken another swing at a new version released late in 2017.

The new app is intended for mine control room operators to monitor the latest seismicity and communicate event alerts and exclusion areas depending on site specific rules. Each site can setup their own event alert and exclusion settings in the Basic Seismic Monitoring (Admin) application and then the main application is a simplified interface for the viewer.

Key features include:

  • Automatic events updating (no need to keep pressing “Reload Data”!).
  • Popup event alert notifications (to alert user when window is hidden/minimised).
  • Popup system alert notifications (triggered from threshold time without new events).
  • Plot exclusion areas and isolate single mine areas (e.g. single level plans).
  • Automatic View – quick zoom/rotate to the exclusion areas on screen.
  • Distance measurement – get the distance from any survey point to the nearest event alert.

There are two videos uploaded at the page below; one to show you how to do the initial setup in the Admin window and another for the basic user in the main monitoring window. If your root looks different to the video, you might need a root update. The process is quick! Just contact support. 
https://mxrap.com/training-videos/monitoring-app/

We are also working on a few more features for the app and will hopefully release another update soon in 2018. Additions should include:

  • 3D text from DXFs
  • Non-spherical exclusions (cylinder or box)
  • Alternate event marker style
  • Improved data reload speed
  • Popup event query window (for source parameters)
  • Enable/disable auto-clipping
  • Event comments included in the table

If you have any questions or comments, feel free to email support@mxrap.com.

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