Jefferys – Bullen Table and other earthquake knickknacks

In summary, the conversation is about finding the equation to determine the distance or angle from a seismic station to the epicentre of an earthquake using the difference in travel times between S and P waves. The second part of the conversation involves finding the intersection of three circles on the surface of the Earth using their radii and coordinates. The assignment mentioned involves estimating the distance to the epicentre using a Jefferys – Bullen Table and triangulating the location on a globe. The conversation also mentions searching for formulas on a website, with a correction on the spelling of 'Jefferys'.
  • #1
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I was wondering what is the equation that gives the values in a Jefferys – Bullen Table?
Specifically, what’s the equation for finding the distance (or angle) from a seismic station to the epicentre of an earthquake using the difference in travel times between S and P waves as recorded by the station?

Oh also, more of a math question, but I’ll use it for triangulating the location of the epicentre: How would one go about finding where 3 circles on the surface of the Earth intersect (if you know the radius of each circle and their coordinates on the Earth) mathematically?

My assignment is really to do this by estimating what the distance to the epicentre would be by looking up values on a Jefferys – Bullen Table and then triangulate them by drawing circles on one of those big globes that you can use chalk on. As you can imagine, it’s a very messy process. I already did it and figured out where the epicentre was; I just want to know how to do it mathematically.

Thanks!
 
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  • #2
Anyone? I've tried googling to no avail...
 
  • #3
Sorry Did the same, no luck too. I'm afraid internet is not the answer to all the questions.
 
  • #4
http://www.igf.edu.pl/~pwiejacz/a/analysis2-wo-ojc.htm

I see formulas on this page

"Analysis of travel time residua at Polish seismological stations

1998-2003"

You just have to spell Jeffrey's name right
 
Last edited by a moderator:
  • #5
LoL, thanks NileQueen. I guess I took the note wrote. It is indeed 'Jeffrey's'
 

1. What is the Jefferys-Bullen Table and how is it used in earthquake studies?

The Jefferys-Bullen Table is a reference table that was developed in the 1950s by British geophysicists Harold Jefferys and Keith Bullen. It is used to calculate the travel time of seismic waves through the Earth's interior, which is crucial for understanding earthquake mechanisms and determining the location of earthquake epicenters.

2. How is the Jefferys-Bullen Table different from other earthquake data tables?

The Jefferys-Bullen Table is unique in that it takes into account the effects of the Earth's curvature and density variations, which can greatly influence the travel time of seismic waves. This makes it a more accurate and comprehensive tool for earthquake studies compared to other tables.

3. Is the Jefferys-Bullen Table still used in modern earthquake research?

Yes, the Jefferys-Bullen Table is still used by seismologists and earthquake researchers today. While there are now computer programs and more sophisticated methods for calculating seismic wave travel times, the table is still a valuable reference tool and is often used as a benchmark to compare results.

4. Are there any other important earthquake "knickknacks" besides the Jefferys-Bullen Table?

Yes, there are many other tools and instruments used in earthquake research. Some examples include seismographs, which record seismic waves, and seismometers, which measure ground motion. Other important "knickknacks" include GPS devices, which can track movement along fault lines, and remote sensing technology for mapping and monitoring earthquake zones.

5. How can the data from the Jefferys-Bullen Table be applied in real-world situations?

The data from the Jefferys-Bullen Table is used for a variety of practical applications. For example, it can help in the early detection and warning of earthquakes, as well as aid in the design of earthquake-resistant buildings and infrastructure. It is also used to better understand the Earth's structure and dynamics, which can have implications for resource exploration and natural hazard mitigation.

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