From: "Larry Cochrane" <cochrane@..............> Subject: Re: WinSDR update Date: Tue, 30 Jul 2002 00:51:06 -0700
Thanks Jon. Please send any info you can on how to do this. Unfortunately I don't have time right now to work on any new features in WinQuake. Hopefully in a few weeks I can work on adding this feature.
Regards,
Larry
----- Original Message -----
From: Jonathan M. Hanson
To: winsdr@..............
Sent: Monday, July 29, 2002 9:46 AM
Subject: Re: WinSDR update
Larry -
I just got off the phone with Lew Katz (Utah Geophysical). It would appear that the simplest way to estimate direction to the quake is by simply plotting particle motion. For example, specify a time window that contains the P wave. Then plot the EW component on the X axis and the NS component on the Y axis. This will give a crude estimate of direction to (or from) the quake. Looking at the first motions would eliminate the reduncy in solution. If velocity sensors are used, I presume that one would want to integrate the data before plotting. Also, it probably would be useful to apply this method to either filtered or unfiltered data just to have a bit more control. An identical approach could be used for other phases but, depending on the particle motion with respect to the line-of-site to the quake, interpretation would be different. Also, one could include the Z coordinate but this might be difficult to interpret unless you put up a 3D box frame on the screen with slider bars so that you could rotate the box (with particle tracks plotted inside the box) in 3D. There are much more sophisticated methods (see for example the Users Manual for PITSA by Scherbaum and Johnson, IASPEI Software Library Vol 5, p. 119) but the simple method outlined here would be easy to implement.
I can delve into this further if you need additional references, etc.
Regards, Jon
Larry Cochrane wrote:
Hi Jonathan,Thanks for the update. On the WinQuake wish list is the ability to plot thedirection based on three components. The problem is I don't know how to dothis so I need to do some research before I can add this feature.Regards,Larry CochraneRedwood City, PSN----- Original Message -----From: "Jonathan M. Hanson" <jhanson@..............>To: <winsdr@..............>Sent: Sunday, July 28, 2002 8:07 AMSubject: WinSDR updateHi Larry -Thanks for the WinSDR update. I have not contacted you since I got mysystem going so here is a brief update.A friend of mine (Lew Katz, Pres. Utah Geophysical) has lent me severalgeophones to play around with. The most intriguing is an Electro-TechEV-17H that he dug out of one of his storage units. I have not beenable to find any information on this unit but it seems to have asomewhat lower frequency response than the Mark Products geophone Ipurchased from you. I have attached a couple of jpegs showing recordedquakes about 60 miles (Huntsville, UT) and a couple of hundred miles(Yucca Mtn, NV) as recorded by this unit on June 2 of this year. Thepicture labeled june14_02 shows both quakes..the first is the Huntsvillequake and the second is the Yucca Mtn quake. The picture labeledjune15_02C shows the Huntsville quake. I would appreciate anyinformation you might have on the EV-17H. I di
d a web search and theonly hit I got on Electro-Tech was one geophone on the SEG "virtualmuseum" site. I suspect my unit was built in the 40's or 50's but thisis pure speculation. I have not yet had the time to build a long-periodsensor but hope to do so shortly.Do you have any short or long term plans of adding some sort ofpolarization filter module to WinQuake? This might allow those usersthat are recording 3 components to get an estimate not only of thedistance to the quake but also direction. There is a rather large amountof mining activity in Utah and surrounding states. A directional filterwould help me sort out the mining-associated activity from other activity.Best regards,Jonathan Hanson__________________________________________________________Public Seismic Network Mailing List WinSDRTo leave this list email WINSDR-REQUEST@.............. with the body of the message (first line only): unsubscribe