“Small moves Ellie, small moves.” is more than a famous quote from the motion picture ‘Contact’, it is also an important mantra for many Scientists. In geophysics, a small increase/decrease in the value of a measurement may easily influence an interpretation…. or “miss”- interpretation. See the image below…. this graphic illustrates how “small moves” in frequency can yield different interpretations of seismic waves. Detecting ground motion from the ocean tides, for example, requires instrumentation which can measure very low frequencies; conversely, detecting the ground motion from the sound of fireworks requires a seismograph that can detect very high frequencies. When we observe ground motion recorded on a seismograph, illustrations can help us begin to interpret the data. Image is courtesy of Peter Bormann, Klaus Klinge and Siegfried Wendt.
On this Christmas Eve, the Pacific Plate’s “Ring of Fire” is very active. In the past 24 hours, several earthquakes with magnitudes M>5.5 have occurred around the Pacific Rim in: Canada, Guatemala, Argentina and Columbia. These events have all been detected in Spring, TX by #RaspberryShake Station #R5DDF operated by Texas Educational Seismic Project. Note that different filters have been applied to the seismograms – see the red text in bottom right corner of image for information.
Over the past 30 days, there have been eight earthquakes, with magnitudes M>2.5, occurring in West Texas. The energy industry’s high-activity in the region is of key interest when monitoring the recent heightened event frequency near Pecos, Gardendale, Ft. Stockton and Mentone, Texas. We do note that correlation does not equal causation. But, we are intrigued. On the map below, the circles represent the epicenters of these earthquakes….it’s a big State!
Did you know earthquakes occur, monthly, in Texas? A recent “large” earthquake with a magnitude M3.0 occurred near the town of Pecos, TX. Earthquakes with magnitudes 2.0 to 3.5 have been occurring more frequently across the State in the past 5 years. There is speculation about the possibility these events are human-induced seismicity – partly because of active oil and gas productivity in the State. Several local institutions have been studying the earthquake activity with a focus on detecting when, and where, the ground shakes. Although these studies discuss correlation of seismicity with energy production and enhanced recovery operations, direct causation has not been confidently established (yet). Regional and local seismic monitoring continues by citizen scientists, academics and private enthusiasts…. and of course by TXESP. Below are some examples of earthquake activity in 2019 within Texas.
DYK that seismographs record *any* ground motion, including local community activities? This week we look at several examples of seismograms from a nearby railroad crossing. Both the EQ1 and Raspberry Shake seismographs can detect the passing trains. Shown below are unfiltered seismograms and associated spectrograms from Raspberry Shake Station RAD87.
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For several weeks TXESP has observed an odd and interesting seismic signal recorded on the EQ-1 seismograph. During the 15:00 UTC hour (locally 9:00 am CST), we observe the seismogram shown below. We are curious if this mysterious, consistent recording is detecting a local scheduled train? ground motion caused by the pool circulating on a program? pumpin at the nearest water station (less than 5km away)? What does it look like to you? Our guess is the train although we have been unsuccessful locating the nearest railroad crossing’s train schedule (its privately owned).
DYK that #seismologists have also served their Country? Help #TXESP continue **contributing to science**, through our service, and go beyond being only users of science!
Historically and currently, seismologists help monitor sub-surface #nuclear #weapons testing. #Seismographs detect the ground motion which occurs after a nuclear #detonation. The ground shaking produces seismic waves which can be monitored remotely by seismologists. This seismogram detected a nuclear explosion in #NorthKorea on 09/09/2016 at 00:30hrs UTC ; it was recorded on an EQ-1 seismograph in Spring, TX, USA.