Important information regarding the operations and status of the TexNet Seismic Monitoring Network.
Due to a software update of the seismological software used for data acquisition, processing, distribution, and interactive analysis used by TexNet, there has been a change in the ML (local magnitude) values shown on our TexNet Catalog. The ML amplitude calculation changed because of a bug that existed in previous versions of the software. This caused a scaling by a factor of two for the zero-to-peak amplitudes in the ground motion. After fixing the software code, ML magnitudes shown on the Catalog for most events decreased by approximately 0.3 (or log10(2)), though, in a few cases, this value is higher or lower. We are working with the software vendor to identify the reason for the discrepancy, and we will make adjustments where appropriate. We are confident in other aspects of the software and TexNet operations.
We understand that this has led to some confusion and we are addressing the issue as quickly as possible. Going forward, any changes to the workflow and processes that define earthquake characteristics on the TexNet Catalog will be made only after externally peer-reviewed papers have been published and there have been discussions with our Technical Advisory Committee. In those cases, we will then notify the public of any changes one month in advance through the “Important Information” link on our web site: http://www.beg.utexas.edu/texnet/catalog.