Distance to the Moon and Earthquakes

[George Ion]

I once (8 years ago) built a table with correlation between moon phases and distances with earthquakes in a certain seismic area. Can't remember where i took the moon distance from, but i would assume from a calculator on a site. It seems there is a strong correlation with moon distance.

I need to populate a table with distances to the moon on certain days to verify it again with a different data set. Distance could be the distance between  the center of the two bodies, no need for distance from a certain pair of coordinates and it can be at midday. If there is a formula that i can put in a spreadsheet. It can be a two body only periodic simplified formula, no need for other factors.

One option would be to do it with Stellarium, but i have to input coordinates and would be time consuming.

Or is  there a formula that i can put in a spreadsheet that can call a Stellarium (or a function on a site) to return the moon distance for a certain parameters.

Like this site gives only perigees and apogees, but i assume it uses a formula.

Edited April 25 by George Ion
Added one more link

[George Ion]

I think i got it all figured out. Since Moon orbit eccentricity is about 5% i think for the purpose of establishing a correlation only, i can approximate and say the angular speed is constant in which case i can use this figure and subsequent formula. I would appreciate for anything better than this that would be manageable in a spreadsheet.

Edited April 26 by George Ion

[dnl]

To show a correlation could you just use the info from here.

https://www.timeanddate.com/astronomy/moon/distance.html?year=2024&n=1332

Although Milton Keynes may not be the hotbed of earthquake activity.

And divide the difference by 14 to give a daily value .

Or am I just simplyfing to much

Edited April 26 by dnl

[George Ion]

On 26/04/2024 at 10:25, dnl said:

To show a correlation could you just use the info from here.

https://www.timeanddate.com/astronomy/moon/distance.html?year=2024&n=1332

Although Milton Keynes may not be the hotbed of earthquake activity.

And divide the difference by 14 to give a daily value .

Or am I just simplyfing to much

I got the same thing on the last link in my initial post, but center to center.

What i need is center to center (no specific location on Earth surface), daily . I have a data set with with 5424 eqs > 4 in Greece since 1940 (yes it is a very important seismic area, probably most active in Europe). I cannot possibly go in there to fill that data manually and on the given link there's only apogees and perigees. The only way to do it is a formula derived from Moons ecliptic which i think i have figured as i said in my first reply.

Things would be much more interesting with location, but it is not part of the same equation. The Earth surface acceleration component follows a law of Earth rotation against self, it varies on a 24 hours cycle and it cold be biggest around the time Moon is at zenith and would vary with latitude, Moon plane inclination, etc.. Much more complicated. I was looking yesterday for John Walker's email and found out he was dead.

But this can't be done in a spreadsheet LOL. This is where the big boys with supercomputers with AI and vocal interface should step in.

Hard to believe they didn't figure it yet.

Edited April 28 by George Ion

[George Ion]

I think i found it. It was in... Wikipedia. However, when i tried to  use it, i saw d is on both sides of  the equation.

Edited Friday at 17:22 by George Ion

[Gfamily]

You can use the NASA Horizons system to get details of the Earth Moon distance 

https://ssd.jpl.nasa.gov/horizons/app.html#/

For the appropriate settings, this may help

This gives you a day by day distance (and relative speed) 

As it will only allow about 90K records, your time interval can't be less than about 8 hours without shortening the date range