Force Balance Vertical Seismometers

[g...@theconnection.com]

Hi Everyone,

I see a lot of discussion about the Raspberry Shake seismometers, how are they with the far distance shakes coming from the South Pacific. Are there any members with a Force Balance Vertical unit that Brett Nordgren and Dave Nelson developed several years ago. I have a couple, one a vertical and also a horizontal see: https://www.theconnection.com/  It would be good to compare notes on our FBV’s.

Take Care,

Gary

 

 

 

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[Pete Rowe]

Hi Gary

I have a Yuma2 running in Los Altos. 

My friend, Alan George, also built one. His is at his son's house in San Diego. 

Go to www.rowelabs.com. 

Push the seismometer button. You will see seismograms from each of us.

We have two filter setting so we see teleseisms and local quakes.

I haven't been on the psn list in a long time. I was one of the early PSN geeks.

Come visit me sometime. 

Pete Rowe

Pete...@rowelabs.com 

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[Bob Hammond]

Gary,

Here's some screen shots of the Molucca Sea event (2026-04-01 22:48:12 UPDATED: (M7.4) Molucca Sea 1.2 126.3) for a Raspberry Shake in Mullan ID, my MOHO Pro, and my Guralp CMG-40 T 1-second instruments.  I am absolutely sold on the MOHO.

Bob

Top trace in WinQuake is the Guralp CMG-40T 1-second instrument.  Bottom trace is the MOHO Pro.  They are running side by side.

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[Bob Hammond]

My installation:

Moho Pro:

[Robert Beer]

Gary,  et al.,

I built a couple of the Yume-2 seismometers that are running in Bluffton, Ohio.  I am attaching screenshots of the event.  The first is one of the Yuma's and the second is a national array seismometer in Columbus Grove, Ohio.  I am using the Terrashark 3-channel 24-bit A/D from Angel Rodriguez on a Beaglebone Black.  The data is from Earthworm and the LLZ channel is decimated (DecimationRates    "5 4").  Both are plotted with Philip Crotwell's seisplotjs Javascript package, https://github.com/crotwell/seisplotjs.  I wrote the Javascript web app running on the Beaglebone  SBC.

Comments and questions are welcomed.

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Bob Beer <r-be...@onu.edu>

[g...@theconnection.com]

Nice work Bob. To keep out the atmospheric noise, I tried 3 methods, first was a simple Styrofoam box, still noisy, next was a ¼” thick Plexiglas sealed box, still noisy. Finally I ended up with ½” sealed steel case, now very quiet. It takes learning to do this. Are the Raspberry Shake units sealed from the atmosphere?

Take Care,

Gary

 

 

 

From: psn...@googlegroups.com <psn...@googlegroups.com> On Behalf Of Bob Hammond
Sent: Saturday, April 4, 2026 5:28 AM
To: psn...@googlegroups.com
Subject: Re: [PsnList] Force Balance Vertical Seismometers

 

My installation:

 

 

Moho Pro:

 

On Sat, Apr 4, 2026 at 5:19 AM Bob Hammond <propg...@gmail.com> wrote:

Gary,

 

Here's some screen shots of the Molucca Sea event (2026-04-01 22:48:12 UPDATED: (M7.4) Molucca Sea 1.2 126.3) for a Raspberry Shake in Mullan ID, my MOHO Pro, and my Guralp CMG-40 T 1-second instruments.  I am absolutely sold on the MOHO.

 

Bob

 

 

 

 

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[Brian Kuschak]

I’m still running two Yuma-2 FVBs in Washington and Oregon.  

Haven’t updated my page in years and some details are out of date now, but the data plots are live:
https://www.groundmotion.org/

One of the FBV was deployed to a quiet remote site:
https://sites.google.com/view/personal-projects-brian/home/seismic-station-deployment

I’d like to build a MOHO Pro at some point.

Brian

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[Bob Hammond]

Gary,  what you don't see inside the foam box is a sealed industrial polystyrene case.  I don't have a photo of it right now.  I agree, a sealed steel or thick aluminum case would be better.  More mass too which helps.

The Raspberry Shakes are not sealed.  The plot I sent is from a RS located on the floor of a fire station near an active mine and I'm surprised how well it does.  I don't like how expensive it is to get data from the RS but that's their business model.

This is a good alternative to the RS:  https://github.com/erellaz/seisberry

Bob

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