Mount Rainier seismicity is normal

Recently there has been a false report circulating that Mt. Rainier is suddenly showing seismic tremor activity — The report is not true. The signal being referenced is actually radio interference, most likely due to rime ice buildup on the antenna of one of our seismic stations. That station, STAR, is one of the last remaining old analog sites on the mountain and uses very low-power radio transmission to send data down to a receiver site. This older, low-power system is susceptible to weather-related interference and the recent stormy weather is certainly the culprit.  There is currently no unusual seismic activity at Mount Rainier. 

 

The following two seismograms are from the same recent period of time at two station high on the mountain; one is STAR located just west of the sumit and the other RCS  to the north-east and located only about 4 km (2.5 miles) away.

 

 

Note that there are periods on the above STAR seismogram where the signal looks almost normal but other periods when it is very strong.  As the radio receiver looses signal, like the static you might hear on your car radio when a signal fades, the seismic signal becomes just strong noise.

 

 

The above seismogram is the same period of time on station RCS with annotations for examples of typical signals seen on this high station surrounded by glaciers, rock cliffs and susceptible to wind. Any of the larger "glacier slips or rock falls" on this would be easily seen on station STAR if it was working properly.

 

Any unusual seismic activity (significant earthquakes or volcanic tremor) in the volcano would show up on both of these stations (and several others that are on or near the volcano) and would be detected and reported by us within a short time, such as was done back in July of this year. 

 

Below is another comparison of seismograms (one minute long in this case) of 5 different stations for the exact same time yesterday during which station STAR still has telemetry problems. This shows the waveforms recorded by these stations from a small quarry explosion located 32 km (~20 miles) north of Mount Rainier.  The top three stations (RCS, RCM and STAR) are located high on the mountain while stations PANH and MILD are on the lower flanks.  It is clear that STAR is NOT showing ground vibrations but random noise.

 

 

Unfortunately, sloppy journalism by non-scientists who don't understand seismology nor check with those that do can generate confusion in the public and more work for those who need to correct the clearly incorrect information.  It is no wonder that some publications are only considered tabloids and should never be believed.