LITTLE PICTURE: Comparing Seismograms From the M6.4 Alaska Earthquake 08/12/2018

A large #earthquake shaked #Kaktovik, #Alaska at 14:58hrs UTC (or 09:58 am CST).  The #focaldepth was 9.9kms and the #epicenter is ~48 polar degrees away from Spring, TX.  The #seismograms below present the #groundmotion recorded in Spring, TX from the M6.1 event.  The #figure shows a #comparison of seismograms recorded on two different #seismicinstruments at the same location – observations of differing #technologies and their associated #instrumentation sensitivities.

Top Image: Recording from the #EQ1 #EducationalSeismograph with a 10Hz filter applied.

Bottom Image: Recording from a #RaspberryShake with a bandwidth filter 0.1 to 1.2 Hz.

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Interpreting a Seismogram: Indonesia 09 August 2018

Recording global #teleseismicwaves, particularly large #magnitude earthquakes, is exciting, but the quake itself has the potential for damages and a very dangerous event.  As #geophysicists, we seek to further our understanding of the Earth’s #geology below the #crust.  These large quakes give us this research opportunity,  The #seismogram below presents the #groundmotion recorded in Spring, TX from the 08/09/2018 05:25hrs UTC magnitude M6.9 powerful #Indonesianearthquake.  An interpretation of the #wavephases is also provided.  The seismogram was recorded on an #EQ1 #EducationalSeismograph.

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The Generous Blessing Of HOPE: Part 2

** #SCIENCE PHOTOS ADDED ** Thanks to our generous #donors, we raised enough money on our #GoFundMe campaign to build (and donate) the #shakeboards seen below.

TXESP had the honor of hosting the #scienceactivity at the #Willis Community Breakfast on 06/27/2018.  Watching the site of giving and #service reminded us that our mission to share #scientificknowledge with the public is a great gift to give. Photographs demonstrate shake boards which facilitate learning concepts in: #geology, #geophysics, and #geohazard #engineering.

 

TEACHING MOMENT 2: Wave Propagation

#TeachingMoment 2:  This week, we have observed a very unique #seismic phenomenon through our #TX/#MA research collaboration.  While #Texas is close to #tectonicplatesboundaries, and #Massachusetts is located within a “stable” plate interior, the #teleseismicwaves may arrive at our two stations at different times!  When global earthquakes occur far enough away (>100 pol deg) from TX/MA, we can observe a #timedelay on the #seismographs (see below). 

The three examples shown demonstrate how these specific earthquakes arrived ~12 to 13 minutes earlier in #Boston than in #Texas !!  This is an effect of #wavepropagation, or how a seismic wave travels through the Earth.  Why do you think the seismic waves arrived ~12 to 13 minutes later in Texas?  The time difference is due to the type of geology between our two stations, how fast waves move through different types of #rocks, and overall distance (kms) between monitoring stations.

Shown below: Three #educationalseismograph recordings of #global earthquakes.  Top: Station E1TX (Spring, TX) operated by #TXESP.  Bottom: Heath School, Brookline (#Boston, MA) operated by #BCESP.

#DONATE to #TXESP: https://www.gofundme.com/send-txesp-to-agu-in-washington-dc

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The 05 August 2018 Indonesian earthquake.

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The 07 August 2018 Greenland Sea earthquake.

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The 09 August 2018 Indonesian earthquake.

 

TEACHING MOMENT: Guatemala

#TeachingMoment:  On 09 August 2018 at 19:21hrs UTC, a moderately-sized M5.6 #earthquake occurred.  If we compare two #seismographs, one located in Spring, TX and the other located in Brookline, MA, we observe a very common phenomenon – the #seismicevent is detected in #Texas, close to #tectonicplatesboundaries; but, the same event is not detected in #Massachusetts, located within a “stable” plate interior.

Shown below: Comparison of two #educationalseismograph recordings of an earthquake in #CentralAmerica.  Top: Spring, TX.  Bottom: Brookline (#Boston), MA

#DONATE to #TXESP: https://www.gofundme.com/send-txesp-to-agu-in-washington-dc

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Twice the Dice – Greenland Sea and Columbia

On 07 August 2018, two #earthquakes were recorded by Station #E1TX.  The #epicenters of both quakes are shown in the #maps below.  The first event, in the #GreenlandSea was at 13:57hrs UTC, a strong M5.8 and a shallow #focaldepth of 10 kms.  The second event, 2 hours later, occurred in #Columbia at 15:53hrs UTC, M5.4 and a deep focal depth of 148 kms.  It is always fascinating that we can detect #teleseismicwaves traveling across the globe!  The Columbian #seismogram is a nice recording of several seismic #wavephases.

Shown below: A map of the epicenters (highlighted in blue) of the two earthquakes on 08/07/2018.

#DONATE to #TXESP: https://www.gofundme.com/send-txesp-to-agu-in-washington-dc

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Screenshot of the two moderate earthquakes recorded at Station E1TX

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Epicenter of the 08/07/2018 M5.8 Greenland Sea earthquake.

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Seismogram of the 08/07/2018 Greenland Sea event.

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Epicenter of the 08/07/2018 M5.4 Columbian earthquake.

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Seismogram of the 08/07/2018 Columbian event.

Trio Shake Guatemala

On 04 August 2018, two similar #earthquakes shook #Guatemala.  The #epicenters of both quakes were proximal to each other (see in map below).  The first event was at 05:46hrs UTC, M4.9 and a depth of 37.7 kms.  The second event, 5 hours later, occurred at 10:27hrs UTC, M5.1 and a depth of 35 kms.  

Today, 09 August 2018, the largest of three recent Guatemalan earthquakes occurred at 19:21hrs UTC with a magnitude M5.6 and a focal depth of 30.2kms. If you look closely, the three #seismograms look very similar suggesting the #seismicwaves traveled similar paths towards Station #E1TX, operated by #TXESP.

Shown below: A map of the epicenters (highlighted in blue) of the Guatemalan earthquakes on 08/04/2018 and 08/09/2018.

#DONATE to #TXESP: https://www.gofundme.com/send-txesp-to-agu-in-washington-dc

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Screenshot on 08/04/2018 of two Guatemalan earthquakes.

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Epicenter of the 08/04/2018 at 05:46hrs UTC, M4.9 earthquake.

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Seismogram of the 08/04/2018 at 05:46hrs UTC event.

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Seismogram of the 08/04/2018 at 10:27hrs UTC event.

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Epicenter of the 08/04/2018 at 10:27hrs UTC, M5.1 earthquake.

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Screenshot of the 08/09/2018 at 19:21hrs UTC M5.6 Guatemalan earthquake.

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Epicenter of the 08/09/2018 M5.6 Guatemalan earthquake.

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Seismogram of the 08/09/2018 M5.6 event.

Missouri, DYFI?

#Missouri residents, were you awoken this morning by a light #shake or rattling noise?  Today at 09:56hrs UTC (04:56 CST) a small #magnitude M2.6 #earthquake occurred near #WestPlains.  We wouldn’t expect you to feel this earthquake, but it’s possible it may have made your knees wobble – let us know!

Shown below: A map of the #epicenter (highlighted in blue) of the West Plains, Missouri earthquake on 08/03/2018.

#DONATE to #TXESP: https://www.gofundme.com/send-txesp-to-agu-in-washington-dc

03082018_0956_map_Missouri

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A closer look at the El Salvador seismogram recorded on the EQ1 Seismograph.

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Epicenter of the July 27th, 2018 Offshore, Northern Atlantic Ocean M5.1 earthquake.

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Comparing the N. Atlantic seismograms recorded on the EQ1 and Raspberry Shake Seismographs.