(03-19-2025, 07:49 PM)ironyak Wrote: This uneven expansion partially helps answer my question as to why the daily tilt pattern happens at all, but not why it appears to always be in an inflationary direction in the data provided..
And therein lies the reason for my thoughts in the first place. Which for me is the
unusualness of seeing a diurnal effect superimposed over an inflationary event. We usually see the diurnal when it is able to show up because of no other influences. When the tilt is going up or down it is usually too much to allow the diurnal to be seen at the same time.. so.. looking back, again, at what I posted to begin with.. #57 in this thread, in response to kalianna I posted..
(03-11-2025, 02:11 AM)MyManao Wrote: (03-11-2025, 01:45 AM)kalianna Wrote: But if atmospheric temps affected tilt..
Seasonal.. I get it but can’t imagine being able to tease it out of the record. There's so much that goes on over time to sift through.
The thing is under normal.. ie closed off from the surface.. circumstances I am not used to seeing tis type of signal when there’s inflation deflation cycles tied to episodic phases of eruptive activity. The only time I see it on a regular basis is when the inflation is flat..
For instance.. here’s the same time periods of tilt, one week and one month, of the summit of Mauna Loa..
One week..
![[Image: MOK-TILT-1wk.png]](https://volcanoes.usgs.gov/vsc/captures/mauna_loa/MOK-TILT-1wk.png)
One month..
![[Image: MOK-TILT-1mo.png]](https://volcanoes.usgs.gov/vsc/captures/mauna_loa/MOK-TILT-1mo.png)
In which the diurnal is very graphic and the end result is easy to see an average of the daily wave.. unlike Kilauea’s which is rising.
So.. with that go back to my otherwise most recent post.. #84.. where I ask is the steps in the inflation which are cause by the diurnal just noise, or does the diurnal itself add to the eruptive process?
And, to that I'll add.. simplistically..
A volcano is pretty much a giant hydraulic system.
In a closed hydraulic system, with a fluid that itself is minimally compressible, it is easy to visualize how, when a force is applied at one point of the enclosure the fluid then transfers that force through itself to all parts of the system, more or less instantly. In this way a break system on a car transfers the force of a driver’s foot on the break pedal to the breaks at all four wheels and slows the vehicle. The driver sits comfortably in the driver’s seat and applies pressure to the break pedal, and the hydraulic system efficiently transfers that energy to the wheels and what started as a few pounds of pressure moving the pedal a few inches turns into enough energy to slow/stop a moving vehicle. Simple closed system hydraulics.
If that same closed break system were to get a hole in it it would then become an open system, and all the energy applied to the pedal would push the enclosed fluids to the opening in the system without exerting pressure elsewhere. Of course there could be an opening that is, relative to the system, small enough it would allow the system to maintain some or most of its pressure and only a small amount of fluid to be leaked out over time while the bulk of the pressure applied to the pedal would still result in stopping the vehicle. In other words there’s some gray between closed and open.
Which is Kilauea, and with that in mind what is the effect of the diurnal?
And, btw, I have been reading this tilt station's data since its inception, and at one point was involved in quantifying how much magma was equal to the rate of change being recorded. Then, when we were able to compare exact amounts of lava erupted to the amount of tilt recorded, it was pretty much 1 microrad to 1 million cubic meters of lava. So, with these steps in tilt being as much as 1/2 microradian they can amount to the over all volume being recorded being a fair amount different which ever way they are interpreted.