this is interesting (earthquake related)

[MSaxatilus]

vtunderground,

I'm a hydrogeologist by trade. The blimp you are seeing on your datalogger in your well, while coincidental, is surely not related to seismic activity in Asia. The entire planet is wired with sonic equipment and siesmic instruments that could probably detect the activity over there which allows the geologic communit to triangulate epicenters of siesmic activity, but your pressure transducer would never have the resolution to see such a minute siesmic signal this far away.

Since the graph shows a huge postive spike in the groundwater level, followed by a huge negative spike (a change of like.. 3 feet!!!!), follow by a gradual recovery... it appears more like something large had fallen/or was thrown into your well, and then the well naturally recovered and returned to equilibrium.

We commonly have this problem with kids messing with our monitoring wells, even though they are locked. Kids are pretty creative.

In addition, the graph does show some routine rises and falls, similar to a tide cycle? (I don't know where that well is located) so if its in a wet area and is a shallow well, it could be indicative of something large thumping the ground next to the well. Maybe a tree falling, heavy equipment moving by, etc.

Anyway, that's my guess. But I highly highly doubt it has anything more than coincidence with the Asia event.

Sorry to rain on your parade/thread.

 

[vtunderground]

Ah, I knew there had to be a hydrogeologist on here somewhere!

I'd agree that your theory that something was thrown in the well (or fell next to it, etc....), except for two things. First, our equipment only takes readings every 15 minutes. The positive and negative peaks are actually 30 minutes apart. Second, other wells showed a blip at the same time (though nowhere near as significant).

I believe you're right about the rhythmic rising and falling being related to the moon. This is strange, because this well is in the mountains, and none of our other groundwater wells fluctuate like this. Have you heard of groundwater wells this far inland exhibiting tide cycles before?

 

[eluminator]

I should have said lunar tidal forces instead of lunar tides. Tides bring to mind the surges of the ocean water but actually the entire earth is stretched along a line between the earth and moon.

It does surprise me that your equipment would sense this so maybe there is another explanation. It would shed more light on this if we could see a month's worth of data. Because the moon revolves around the earth once a month, there should be 29 of these "daily" double cycles in a 30 day month.

That's assuming the moon revolves around the earth in the same direction as the earth rotates. I guess it does, but if it goes the other way there would be 30 of these "daily" double cycles in a 29 day month.

On further thought it would be interesting to know how the peaks and valleys correspond to the high tide and low tide in that area.

 

[vtunderground]

[ QUOTE ]
eluminator said:
It would shed more light on this if we could see a month's worth of data. Because the moon revolves around the earth once a month, there should be 29 of these "twice daily" double cycles in a 30 day month.

[/ QUOTE ]

30 days worth of data

 

[eluminator]

Okay, I looked at the data. Not the best graph in the world, but after expanding it by a factor of 5 with paint, its usable.

I'm betting you are indeed sensing tidal forces. I'll even go out on the limb further and bet you did detect the earthquake. I'm not a geologist, just the village idiot, so take that with a grain of salt.

To prove it better one would need at least two months of data. The sine waves from the first to the fifth of the month were too weak, so I started on the sixth and went to the 20th when the max occurred at about the same time of day as the sixth. That makes 14 days with 29 cycles. So 28 days would have 29 "double cycles". Close enough for me.

I also found a "moon calendar" on the internet and noted the neap tides (weakest tides) occurred on Dec 5 and Dec 19 and the spring tides (strongest tides) occurred on Dec 12 and Dec 26. That seems fairly close to your graph.

The neap tide on Dec 5 helps to explain the weak sine wave from Dec 1 to Dec 5, but not completely. Did you fix your rig on the 5th?

By the way, if you put more data here I won't necessarily analyze it. Besides it would be good if another independent "scientist" confirmed my findings.


EDIT EDIT EDIT
I made a mistake counting cycles. It's actually 27 double cycles in 28 days. Whew, for a minute there I just proved the moon orbited the earth backwards /ubbthreads/images/graemlins/smile.gif All's right with the world now though, and my bet still stands.

 

[vtunderground]

Cool, I agree with your analysis. The whole tidal thing makes more sense than the explanation one of my co-workers gave me... he guessed that the water table was fluctuating up and down because of drinking water wells in the city nearby.

 

[gadget_lover]

I can imagine a wide, shallow water table that streaches over a large area being able to act as a super sensitive transducer, especially if it's trapped just right ..... A movement of 1/1000 inch (pushing up) across 10 sq miles = how many inches of rise in a 6 inch pipe if that pipe's the only low resistance opening?

I understand an earthquake center in New York did register the quake.

Daniel

 

[eluminator]

If it was humans using water in a nearby city then I would think the double cycle would have a period of 24 hours. But it appears to have a period of almost 25 hours. 27 double cycles in 28 days. This is exactly what would be expected if it was the moon that was doing it. Of course that's what I wanted to find so it's not surprising that I found it. /ubbthreads/images/graemlins/smile.gif Still I think it is so.

Further, it's hard to imagine why water consumption would follow a sine wave with a frequency of 2 per day.

It sure looks like its the moon and not human activity. I am still surprised that your equipment can measure this, but I'm still betting that it is. The underground aquifer thing being part of the mechanism sounds better than anything I can come up with. Well actually I haven't come up with anything.

To get further confidence that we are seeing the earthquake, the time of occurance would have to be pinned down. Maybe you did this already. We'd have to know what time is on the graph. Local time or GMT (or whatever they're calling world wide time these days).

I wonder if the USGS is aware of this. If you encounter a scientifically minded person there, it would be interesting to see what he or she thinks. If you need more data analysis I might be persuaded, especially if it looks like we will get a Nobel prize for this /ubbthreads/images/graemlins/smile.gif