Comparing Seismograph Technology: NICARAGUA

COMPARING TECHNOLOGY – NICARAGUA – 01/24/2020 at 21:59 UTC (3:59 pm CST) a preliminary magnitude M5.3 earthquake shook the Central American country and was recorded here in Spring, TX. Shown are comparisons of seismograms and spectrograms (frequency plots) from EQ1 and Raspberry Shake seismographs collocated in Spring, TX. NOTE the lower frequency threshold for the EQ1 instrument.

24012020_2159_extractComparison_BP0.5to1.0_R5DDFandE1TX_Nic24012020_2159_extractFreqComparison_R5DDFandE1TX_Nic24012020_2159_map_Nic

Small Moves Ellie, Small Moves

“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.

SeismicFrequencies

A Christmas Ring of Fire

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.

23122019_1547_extractR5DDF_LP1.2_Guat
M5.8 in Guatemala on 12/23/2019 at 15:47 UTC
23122019_1913_1949_2056_extractR5DDF_BP4.0to20.0_Canada
M5.7, M6.0 and M6.0 in Canada on 12/23/2019 at 19:13, 19:49 ad 20:56 UTC
24122019_1643_extractR5DDF_LP2.0_Arg
M6.0 in Argentina on 12/24/2019 at 16:43 UTC
24122019_1903_extractR5DDF_BP0.2to1.2_Columbia
M6.0 in Columbia on 12/24/2019 on 19:03 UTC

The Dynamic Earth: Cracking it Up in West Texas

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!

23122019_0113_map_last30daysTX

Bigger in Texas?

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.

Read more from UTIG/TexNet here , TAMEST here, and Southern Methodist University here.

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Trains and Railroad Crossings

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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What’s this signal? Train? Electronics?

Give to “Seismographs in Houston Schools” >>>https://www.gofundme.com/f/seismographs-in-houston-schools

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).  

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Screenshot of a mysterious, consistently occurring signal, during the 1500 UTC hour, is recorded on the EQ1 at IRIS’ Station E1TX.
17112019_1500hr_extract_train
Seismogram of a mysterious, consistently occurring signal, during the 1500 UTC hour, is recorded on the EQ1 at IRIS’ Station E1TX.
17112019_1500hr_extractRAD87_BP3.0to6.0_train
Seismogram of a mysterious, consistently occurring signal, during the 1500 UTC hour, is recorded at Raspberry Shake Station RAD87. A BP 3.0-6.0 Hz filter applied.
17112019_1500hr_extractRAD87_BP3.0to6.0_spectra_train
Spectrogram of a mysterious, consistently occurring signal, during the 1500 UTC hour, is recorded at Raspberry Shake Station RAD87. A BP 3.0-6.0 Hz filter applied.