Two very large #earthquakes are shaking the full Earth this morning – at 5:39hrs UTC (12:39 am CST) a #magnitude M6.6 earthquake shook NW #Australia, and at 09:10hrs UTC (04:10 am CST) a very powerful magnitude M7.3 earthquake shook Laiwui, Indonesia. Reporting states no tsunami warnings were issued. Both events travelled across the Earth and were recorded by #RaspberryShake Station RAD87, operated by Texas Educational Seismic Project (#txesp, http://www.txesp.org) in Spring, Texas, USA. Below are images of both events – filters have been applied.
Initial Reporting of the Damages and Human Losses
A strongly damaging magnitude 8.0 earthquake has shaken Peru early this morning, May 26, 2019 at 07:41hrs UTC (02:41 am CST). Earthquakes of this enormous size and energy occur infrequently and may cause catastrophic human and economic losses. This earthquake was recorded here in Spring, TX by Raspberry Shake Station RAD87. Images shown include un-filtered and filtered seismograms of this event (read associated captions).
Initial Reporting of the Damages and Human Losses
THANK YOU to our anonymous donors this past month – TXESP is so grateful for your generous gifts! We will be using the monies to pay two bills and put the remaining amount towards a future purchase of a few classroom mineral specimens.
With gratitude, we thank you for helping us continue our community STEM outreach mission to further scientific inquiry and facilitate open-ended scientific investigations!
“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.
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).
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.