Energy and moment are two independent measures of the strength of a seismic event. Their physical meaning and how they are calculated was described in a previous blog post. Analysis of the relationship between the energy and moment of events can provide insight into...
Two new charts have been added to the General Analysis application related to assessing hazard with the frequency-magnitude relationship. The new charts plot various hazard parameters over time, or, by time of day:...
As mentioned in the last blog post, a stochastic declustering algorithm has been implemented in mXrap to separate events into ‘clustered’ and ‘background’ components. It can be useful when designing seismic exclusions and re-entry procedures to separate seismicity...
We have added some new event filter options to General Analysis related to ‘background’ activity. ‘Background’ events are generally defined as having low variability in space and time. The new background filters aim to identify events that are clustered in space and...
Moment tensor analysis is a topic that carries a decent level of uncertainty and confusion for many people. So I’m going to lay it out as simply as I can. For this post, I’m not going to go into too many details on how moment tensors are actually calculated. But, I’m...
Moment tensors have been added to the General Analysis application in the recent update. Beach balls and principal axes can be viewed in the General Analysis 3D view. There is also a separate Moment Tensor window with a number of stereonets and mechanism charts. Two...
The a/b value is sometimes used as a measure of seismic hazard but there are some common mistakes made with this analysis and interpretation. What is a/b? The Gutenberg-Richter distribution is a statistical model that describes a log-linear relationship between the...
When you are using the Frequency-Magnitude chart, it can be easy to forget it is log scale and this can distort a few things. Consider the chart below, have you ever thought the Gutenberg-Richter distribution doesn't look right? Think it isn't matching the large...
There are many reasons you might want to store a short snippet of text associated with an event. There are two ways to do this in mXrap; event tags and event comments. Event tags can be used to group events into categories. Example tags might be “suspected blast”,...
You can use selections to filter events in General Analysis. This gives you a lot more freedom than being restricted to the traditional min/max range filters. Follow the steps below to see how you can use this feature to plot the Frequency-Magnitude chart for events...
The distance to survey filter has been around for a while but now we have added a couple of new charts to further investigate the relationship between seismicity and your input surveys. The charts have been added to the General Analysis application, under the Charts...