What data? Watch this… and filter ON!

“Did we detect that LARGE global earthquake?  Maybe it’s “not there”…..I just observe noise”.  On May 14th, 2019, a MAJOR magnitude M7.5 earthquake hit Papua New Guinea.  Here in Spring, TX, operated by Texas Educational Seismic Project, the ground motion was detected very obviously on the EQ1 educational seismograph (see Figure 1a).  On site, we also have a Raspberry Shake seismograph which we hoped had an equally observable response to the massive earthquake (Figure 1b).  Due to mechanical and technological differences between the instruments, we did **not** see the response on the RS.  Or did we?

For over a year, TXESP (and others) have been carefully reviewing the technical capabilities of the Raspberry Shake seismographs compared to different educational seismographs (EQ1, AS1).  One of the most important concepts we are continuously learning is the application of filtering data. In signal processing, a filter is a device or process that removes some unwanted components or features from a signal. Filtering is a class of signal processing, the defining feature of filters being the complete or partial suppression of some aspect of the signal.

Compare the un-filtered / filtered images (Figures 2a/b and 3a/b) – they now appear more similar to each other and we can “easily” see the earthquake recorded by both instruments.

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TEACHABLE MOMENTS: Watching Wave Resonance Frequencies in Action (Philippines)

TEACHABLE MOMENT: Watch the videos, filmed during the shaking of two earthquakes in the Philippines, which provide two excellent visual demonstrations of the physics/engineering concept of a wave’s resonance frequency. When an earthquake’s wave(s) reach the equal an object’s resonant frequency, the object will begin to oscillate with the same period of the wave.

THE BACKGROUND:  In the past 48 hours, two major earthquakes have occurred in the Philippines. A magnitude M6.1 event happened on 04/22/2019 at 21:11 hrs UTC and was 12 miles deep; the latter event was stronger with a M6.4 on 04/23/2019 at 05:37 hrs UTC and was 34 miles deep.

In the first video, found HERE, a sky-rise condominium begins to sway at the same frequency of the M6.1 earthquake surface waves, and thus, water from the rooftop’s swimming pool begins to pour over the side of the high rise building.  Injuries are unknown at this time.  The second video (found HERE) observes a hotel’s chandelier tiers swaying at different frequencies, dependent on the individual tier’s length, in harmony with the M6.4 earthquake’s surface wave periods.  (<<< one “wave” may be comprised of several wave periods convolved together).

Small Turns, Ellie

Have you seen the movie “Contact” ?  In this film, a father reminds his young daughter that small moves adjusting a radio antenna’s frequency is a more effective method to locating a ping back (another radio antenna operator on the same frequency).  Similarly, small moves, or changes, in air temperature affects responses on the EQ1 educational seismograph…..more specifically, it yields a change in volume of the instrument’s dampening oil which, in turn, yields “apparent” ground movement.  Liberally applying the Natural Gas Law, PV=nRT, when the dampening oil is exposed to a rapid increase in air temperature, the oil’s volume also increases.  Another hypothesis is the external air pressure is lower than the oil’s current ambient state – when the garage door is lifted and the lower pressure air rapidly changes in the room, the oil’s responds inversely by increasing its volume.  The hypotheses both suggest that a shift in volume pushes on the sensitive instrument’s balancing arm, causing movement which, in turn, is recorded by the instrument’s sensors.  The result is an “apparent” ground motion event as shown in the image below.

The takeaway – Scientists are users of their instruments, but they need to be learners of their instrumentation – understanding sources of data uncertainty, false recordings, and detection capabilities.


Please consider giving to “Cultivating Citizen Scientists” program; we purchase educational seismic instruments, mineral specimens, and provide onsite curriculum development with our Professional Scientists and Science Education team members.  Each donation is tax-deductible as TXESP is a 501-c3 Non Profit, designated Public Charity.

15042019_1200to1230_TempEffectsEQ1_E1TX

 

 

 

 

Regional Boy Scouts of America Convention, 2019

I can build a structure with candy? Sign me up! LOL!  TXESP hosted an “activity” booth at the 2019 (Houston Area) Regional Boy Scouts of America Convention at Houston’s NRG Arena.  Want to see time fly?  Ask kids and their parents to enter a competition where you create a sturdy and stable structure, using toothpicks and one choice of candy, to withstand shaking from an ‘earthquake’.  TXESP’s shakeboard tried to slide, tilt or crumble the innovative earthquake ‘resistant’ structures in the competition.  We used gummy bears, miniature marshmallows, and jelly beans to hold the toothpicks together – it was sticky but SO MUCH fun!  The goal of the hands-on activity is to understand what structural characteristics yielded the most stable “building” during the earthquake.  Competitors had to consider what basic shapes bring stability, and they learned which materials were best for strength, rigidity, flexibility and shock absorbance.  It is the combination of both concepts which yielded winners in the competitions – take a look at those winning structures (and how they were built) !


Please consider giving to “Cultivating Citizen Scientists” program; we purchase educational seismic instruments, mineral specimens, and provide onsite curriculum development with our Professional Scientists and Science Education team members.  Each donation is tax-deductible as TXESP is a 501-c3 Non Profit, designated Public Charity.

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Comparing Technology, Part 3: EQ1 and the Raspberry Shake

Is there a one-size-fits-all seismograph? TXESP is continuing to compare the detection similarities and interpretation differences between the EQ1 and Raspberry Shake seismographs.  The dynamic Earth has provided several recent seismic events for us to study at our Station in Spring, TX:  Columbia, Nicaragua, El Salvador and Alaska.  We continue to see a moderate to strong correlation of wave phase arrival times between the two instruments…but is this because we are biasing our data set to earthquakes with magnitudes greater than M=5.0?  See the comparisons in the images, below.


Please consider giving to “Cultivating Citizen Scientists” program; we purchase educational seismic instruments, mineral specimens, and provide onsite curriculum development with our Professional Scientists and Science Education team members.  Each donation is tax-deductible as TXESP is a 501-c3 Non Profit, designated Public Charity.

Images comparing and summarizing the recent, moderate-to-large earthquakes in Columbia, Nicaragua, El Salvador and Alaska.

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Fan Fare… Science Stands!

Science Stands! Though funding and public trust may waiver, Science continues to stand strong over the centuries.  Texas Educational Seismic Project’s mission it to facilitate STEM learning by using seismology as an exciting tool!  You can find us teaching at local schools, reaching rural students thru video conferences, large AND small community events, and at National Conferences – with much gratitude, we send you the same message – THANK YOU!


Please consider giving to “Cultivating Citizen Scientists” program; we purchase educational seismic instruments, mineral specimens, and provide onsite curriculum development with our Professional Scientists and Science Education team members.  Each donation is tax-deductible as TXESP is a 501-c3 Non Profit, designated Public Charity.

A collection of thank you notes, ID badges and certificates from STEM events that TXESP has been a proud participant!

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It’s all about the right filter….

Please consider giving to “Cultivating Citizen Scientists” program; we purchase educational seismic instruments, mineral specimens, and provide onsite curriculum development with our Professional Scientists and Science Education team members.  Each donation is tax-deductible as TXESP is a 501-c3 Non Profit, designated Public Charity.


It’s all about the right filter…. have you seen #photographs that look fuzzy? or are too bright? too dark?  Today’s computer applications allow us to remove red eyes, sharpen up fuzzy images, “fix” brightness and darkness… these applications use of #filters to create a better photograph.  We can apply filters to recorded seismic data and create higher quality #seismograms of the Earth’s ground motion.  Review the 3 images below; each image has had a different filter and amplitude enhancement applied to it.  Which seismogram shows the best representation of the highlighted  #earthquake?  What amplitude and filter was applied?  How is each filter changing the image?  Is it better to change the seismogram’s amplitude or frequency content? Why?

A magnitude M5.5 Peruvian earthquake, recorded Station E1TX, is highlighted in yellow.

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