Flat Earth vs Oblate Spheroid: Earthquakes

[M Bornong]

After a large earthquake, will the time and distance traveled by the waves generated provide evidence of a Flat Earth or a Spherical Earth?

https://twitter.com/IRIS_EPO/status/1220848056859611138

Source: https://twitter.com/i/status/1220848056859611138



Source: https://twitter.com/IRIS_EPO/status/1220848266646036482

P Waves
P waves are compressional waves that do not produce much damage. They can move through any type of material and travel at almost twice the speed of S waves. High frequency P waves do not weaken or attenuate as rapidly as S waves so they retain higher frequencies when they arrive at seismic stations. In air, P waves take the form of sound waves and therefore move at the speed of sound, 330m/s at sea level. Some people even report hearing an earthquake (due to the higher frequency P waves vibrating or rustling objects) before they feel the S waves arrival. Typical speeds in Earth are faster: 1450m/s in water and 5000m/s in granite.

https://pnsn.org/outreach/about-earthquakes/eq-waves

Below, I've selected three earthquakes from the past 10 years, large enough to be recorded by monitoring stations over a vast distance. The monitoring stations were chosen to be similar distances from the epicenters based on a global model, and similar heading, but large distance between based on a flat earth model.



July 14, 2019, 6.6M Western Australia, 05:39:23 UTC

Reporting Station: Distance from Epicenter Time of P-wave Arrival
Puerto Nateles (MG05) 12142 km 05:58+ UTC
Babbage River ((E28M) 12299 km 05:58+ UTC

November 13, 2016, 7.8 M, South Island, New Zealand, 11:02:59 UTC

Reporting Station: Distance from Epicenter Time of P-wave Arrival
Tonquist (TRQA) 9454 km 11:15:30+ UTC
Univ of Southern CA (USC) 11018 km 11:16:31+ UTC

February 27, 2010, 8.8 M, Near Coast of Central Chile, 06:34:13 UTC

Reporting Station: Distance from Epicenter Time of P-wave Arrival
Univ of Southern CA (USC) 9111 km 06:46:30 UTC
Kahutara (KHZ) 8984 km 06:46:30- UTC

https://www.iris.edu/app/station_monitor/#Today//welcome/


Even with variations of the speed of P-waves through different mediums, I would have a hard time justifying the Flat Earth Model.

 

[Priyadi]

Nice findings. Here is the website where we can get the visualizations for other earthquakes.

http://ds.iris.edu/spud/gmv

There are plenty of other visualizations here:

http://ds.iris.edu/spud/

 

[Mick West]

I remember some research on people posting "Earthquake!" or similar on twitter, and the timestamps could be correlated with the location.

Maybe something like this:

https://www.researchgate.net/public...n_and_Earthquake_Reporting_System_Development

Twitter has received much attention recently. An important characteristic of Twitter is its real-time nature. We investigate the real-time interaction of events such as earthquakes in Twitter and propose an algorithm to monitor tweets and to detect a target event. To detect a target event, we devise a classifier of tweets based on features such as the keywords in a tweet, the number of words, and their context. Subsequently, we produce a probabilistic spatiotemporal model for the target event that can find the center of the event location. We regard each Twitter user as a sensor and apply particle filtering, which are widely used for location estimation. The particle filter works better than other comparable methods for estimating the locations of target events. As an application, we develop an earthquake reporting system in Japan. Because of the numerous earthquakes and the large number of Twitter users throughout the country, we can detect an earthquake with high probability (93% of earthquakes of Japan Meteorological Agency (JMA) seismic intensity scale 3 or more are detected) merely by monitoring tweets. Our system detects earthquakes promptly and notification is delivered much faster than the announcements that are broadcast by the JMA.

It's being used for small earthquakes, and you'd need a big one to do any calculations of the shape of the Earth.

 

[M Bornong]

I remember some research on people posting "Earthquake!" or similar on twitter, and the timestamps could be correlated with the location.

The European reporting agency will often post an alert with approximate location based on web traffic before seismic reports come in.


Source: https://twitter.com/LastQuake/status/1221788477248937985


They've put out a couple of animations showing how quick they start getting reports.

Source: https://twitter.com/i/status/1221011123836682244


For a global response, it would probably take a 9.5 M or 1883 Krakatoa eruption type event, so let's hope that doesn't happen too soon.

 

[M Bornong]

I remember some research on people posting "Earthquake!" or similar on twitter, and the timestamps could be correlated with the location.

Maybe something like this:

https://www.researchgate.net/public...n_and_Earthquake_Reporting_System_Development

Twitter has received much attention recently. An important characteristic of Twitter is its real-time nature. We investigate the real-time interaction of events such as earthquakes in Twitter and propose an algorithm to monitor tweets and to detect a target event. To detect a target event, we devise a classifier of tweets based on features such as the keywords in a tweet, the number of words, and their context. Subsequently, we produce a probabilistic spatiotemporal model for the target event that can find the center of the event location. We regard each Twitter user as a sensor and apply particle filtering, which are widely used for location estimation. The particle filter works better than other comparable methods for estimating the locations of target events. As an application, we develop an earthquake reporting system in Japan. Because of the numerous earthquakes and the large number of Twitter users throughout the country, we can detect an earthquake with high probability (93% of earthquakes of Japan Meteorological Agency (JMA) seismic intensity scale 3 or more are detected) merely by monitoring tweets. Our system detects earthquakes promptly and notification is delivered much faster than the announcements that are broadcast by the JMA.

It's being used for small earthquakes, and you'd need a big one to do any calculations of the shape of the Earth.

Looks like we have a worldwide event with infrasound and barometric pressure readings.