Station E1TX has two seismographs – an EQ-1 Educational Vertical Seismograph (sold by Ward’s) – and a less expensive, “plug-and-play” Raspberry Shake. While it may be assumed that the RS is not as technologically advance as the EQ-1, we have observed that the RS detects higher frequencies more often than it’s counterpart (the EQ-1). Interesting, one of the disadvantages of the EQ-1 is that it does not allow users to apply high pass frequency filters; whereas the RS enables users to easily filter data for low, high and band range frequencies. The very large M6.8 PNG earthquake on 29Mar2018 at 21:25hrs UTC showcases this scenario. Further, the RS’s seismogram recorded many wave phases, and thus TXESP has interpreted this event robustly.
Below: Shown is a screenshot from the EQ-1 seismograph compared with an extracted (and interpreted) seismogram from the Raspberry Shake. Very intriguing! To note, the epicentral distance is 112 pol deg and the focal depth is 35kms.
Station E1TX is recording the ground water movement across South Texas following last evening’s/early morning severe storms. The increase in amplitudes, we interpret, is due to the rain waters in South Texas emptying into the watersheds and heading South.
Below: Shown is Station E1TX’s seismograph on 29 March 2018 as of 15:33hrs UTC (10:33 am CST), cumulative precipitation totals across South Texas, and weather measurements during the time of the storms (in UTC). Storms rolled through Houston approximately 3:00 am CST (8:00 hrs UTC).
Note the increase in high frequencies beginning 09:00 hrs UTC (04:00 am CST).
For Houston, shown are current weather measurements. Courtesy of Weather Underground.
Total precipitation for the last 24 hrs (range was from 2″ to 9″ in the mapped area). Map courtesy of Weather.com.
TEACHABLE MOMENT: Now you can see it, now you don’t! Our last post emphasized the absence of recorded seismic data providing input into our Earth models – 25Mar2018 is a perfect example. Station E1TX successfully recorded the M6.4 Indonesian earthquake, but did not record a discernible event of the M6.6 PNG earthquake hours later. What are possible hypotheses to explain the recordings?
Below: Shown is Station E1TX seismograph on 25 March 2018. The black arrows indicates the first arrivals of the M6.4 Indonesian earthquake.
Below: Shown is Station E1TX seismograph on 26 March 2018. The Raspberry Shake, in this comparison with the EQ-1, does show a low-quality seismogram of the M6.6 PNG earthquake.
M6.6 in PNG
TEACHABLE MOMENT: A “Quiet” Day in the “Neighborhood” TXESP frequently emphasizes the absence of recorded seismic data also provides input into our Earth models. The absence of a seismic event may have several interpretations: the Station location is too far to detect an earthquake, an earthquake may have a a small magnitude, the geology doesn’t change significantly between the epicenter and the Station, intrusive geologic features may inhibit seismic wave propagation (a large body of water = ocean), the seismic acquisition array was not sufficiently planned, etc…. the list may be long!
Much of the time, the absence of data is the significant driver of uncertainty in Earth and Geophysical models.When we chase “the one solution”, Scientists generally gain more questions than answers. AND. “THIS IS A GOOD THING” ** !!
An assumed seismically “quiet” day in South Texas. Why?
Below: Shown is Station E1TX seismograph on 22 March 2018. The two black arrows indicate when a major change in air temperature occurred while opening up the garage door.
Texas Educational Seismic Project has been invited to host a booth, and volunteer in other aspects, at the Boy Scout Scout Convention. This is an opportunity for you and your family or organization impacting youth by interacting with them from STEM activities. Exhibits may be a launching point for your path towards a new career or hobby in STEM
Come participate in this amazing event, April 14, 2018 from 10a to 3p at the NRG – it’s open to all including families and IT IS FREE! Further, scouts can even earn badges at mini-sessions !
To see a short 2 minute video showing a wide sample of last year’s activities, click HERE
AN EARTHQUAKE IN HOUSTON? Yes indeed, and it’s not abnormal!!
The magnitude 3.1 earthquake occurred in Houston, Alaska… The event occurred on March 14th, 2018 at 0903 hours UTC. The focal depth was approximately 26 km deep. Want to learn more?
A very large magnitude (aftershock?) earthquake of M6.8 began shaking PNG, again. The event was 110 polar degrees, including crossing the Pacific Ocean, from Station E1TX. It occurred on 08March2018 at 17:39hrs UTC. Due to the large epicentral distance between the station and PNG, Station E1TX DID detect and record the PP, PPR and the Rayleigh/Love (surface) waves appear on the seismogram below.
Surface waves (black arrows) from the 09Mar2018 M6.8 PNG earthquake at 17:39hrs UTC.
Map of the 09Mar2018 M6.8 PNG earthquake at 17:39hrs UTC.
A very large magnitude (aftershock?) earthquake of M6.7 began shaking PNG, again. The event was 120 polar degrees, including crossing the Pacific Ocean, from Station E1TX. It occurred on 06March2018 at 14:13hrs UTC. Due to the large epicentral distance between the station and PNG, Station E1TX DID detect and record the PS, PPS and the Rayleigh/Love (surface) waves appear on the seismogram below.
Black arrows indicate the Surface waves generated from this 06Mar2018 magnitude 6.7 earthquake in PNG.
The one significant wave phase detected at E1TX:
Map of the 6.7 earthquake in PNG.
Although the two earthquakes had small magnitudes of M4.2, these shaking events were significant and felt over a broad area. It occurred on 04March2018 at 23:17hrs UTC AND HOURS LATER AT 03:41hrs UTC. Both events were approximately 6 polar degrees away from Station E1TX in Spring, TX.
Preliminary damage reports and local information may be found here –>> http://www.news9.com/category/225338/oklahoma-earthquakes. Station E1TX detected almost all of the wave phases from these very shallow events (1.9km and 5 kms); Multiple P waves, the Shear wave, and Rayleigh/Love waves appear on the seismogram below.
M4.2 earthquake on 04Mar2018 at 23:17hrs UTC (Event A)
Map of he epicenters of both events
With the acquisition of a new Raspberry Shake, TXESP has additional unlocked opportunities to observe and evaluate local seismic waves. TXESP’s raspberry shake station, AM.RAD87.SHZ or IP address 10.0.0.74, recorded interesting seismic patterns during the Monday morning commute. We are located near a major Big Oil company with 1000+ commuters passing nearby every work day. TXESP observed the seismogram(s) during the peak commuter time from 12:00-15:00hrs UTC (06:00-09:00am CST).
Solid science makes observations, writes deliberate and informative notes, and pose hypotheses from possible patterns of their study. We followed this method for two-month, from 01/22/2018 until 03/02/2018. Here, we present the seismograms from commuter traffic near Station E1TX on Mondays, Wednesday and Fridays. We will analyze the data collected during this quick-investigation of high frequency noise near our Station E1TX; we hope to see a least one pattern emerge, such as “the busiest traffic at the nearby work site occurs at this time.”
NOTE: The times noted are UTC, each horizontal line represents 15 minutes of time and the color helps the user differentiate each line of recording from the one above/below. No filter has been applied.
What inquiries would you have observing these data recordings?