## PSN-L Email List Message

Subject: Re: Time of Quake??
From: "tchannel" tchannel@..............
Date: Sat, 21 Apr 2007 14:02:45 -0600

```Hi Paul, Yes I am using the very  inexpensive \$30?  DataQ 194   I am =
very happy with it, I actually use two of them for two different =
stations.  You can see my .gif's on the Psn new events page.  Ted
----- Original Message -----=20
From: Paul Cianciolo=20
To: psn-l@.................
Sent: Saturday, April 21, 2007 1:38 PM
Subject: RE: Time of Quake??

Ted,

Is it you that is using a DATAQ device...  ?

a 154 or a 158=20
PauLC

-----Original Message-----
From: psn-l-request@.............. =
[mailto:psn-l-request@................. Behalf Of tchannel
Sent: Saturday, April 21, 2007 1:54 PM
To: psn-l@..............
Subject: Re: Time of Quake??

Hi Chris, A question about P travel time?  I read somewhere it =
varies, from __km to __km per second.
Does it vary depending on the material, type of earth, that it is =
moving through?
I have calculated, from recordings, a range of 10,000 to 30,000 =
miles per hour. That's a big range.

I would like to have a better understanding of it.   Thanks, Ted
----- Original Message -----=20
From: ChrisAtUpw@..........
To: psn-l@.................
Sent: Saturday, April 21, 2007 9:34 AM
Subject: Re: Time of Quake??

In a message dated 2007/04/21, Paulc@........ writes:

=20
For the past month I have been working on a horizontal pendulum =
sensor and I am going through my maiden voyage with it.
The clock is accurate to within 10 seconds, I am using the =
Amaseis program, and a 12 bit ADC.

Hi Paul,

The P waves may travel at 8.2 km / sec. You need your clock =
accurate to about 1 sec for practical purposes. I suggest that you keep =
a note of the errors for a day or two. They are often very large.
You can buy a radio corrected crystal clock for less than =
\$20. They are very useful and are accurate to 20 mS. They update every =
hour.=20
You can also visit http://nist.time.gov/ and cross check =
on-line, but do watch out for transient data delays.

I would like to try and compare events elsewhere in the =
world / country to my sensor. At this site I can see various locations.

The question.

If I know in  when in UTC an event occurred, and where.. how =
do I convert that to a UTC time when the event would arrive at my =
location, if ever.
In other words how ho long does it take to get here??

Y=20
ou can calculate arrival time using =
http://neic.usgs.gov/neis/travel_times/=20

from the P to S delay time.

Regards,

Chris Chapman

Hi Paul, Yes I am using the very  =
inexpensive=20
\$30?  DataQ 194   I am very happy with it, I actually use =
two of=20
them for two different stations.  You can see my .gif's on the Psn =
new=20
events page.  Ted

----- Original Message -----
From:=20
Paul =
Cianciolo
To: psn-l@..............
Sent: Saturday, April 21, 2007 =
1:38=20
PM
Subject: RE: Time of =
Quake??

Ted,

Is=20
it you that is using a DATAQ device...  ?

a=20
154 or a 158
PauLC

-----Original Message-----From: psn-l-request@...............
=20
[mailto:psn-l-request@...............On Behalf Of=20
tchannelSent: Saturday, April 21, 2007 1:54 =
PMTo:=20
psn-l@..............Subje=
ct:=20
Re: Time of Quake??
Hi Chris, A question about P travel =
time? =20
I read somewhere it varies, from __km to __km per =
second.
Does it vary depending on the =
material, type of=20
earth, that it is moving through?
I have calculated, from recordings, =
a range of=20
10,000 to 30,000 miles per hour. That's a big =
range.

I would like to have a better =
understanding of=20
it.   Thanks, Ted

----- Original Message ----- =

From:=20
ChrisAtUpw@.......
To: psn-l@.............. =

Sent: Saturday, April 21, =
2007 9:34=20
AM
Subject: Re: Time of =
Quake??
In a=20
message dated 2007/04/21, Paulc@........=20
writes:
For the past month I have been working on a =
horizontal=20
pendulum sensor and I am going through my maiden voyage with=20
it.    The clock is accurate to =
within 10=20
seconds, I am using the Amaseis program, and a 12 bit =
Paul,       The P waves may =
travel=20
at 8.2 km / sec. You need your clock accurate to about 1 sec for =
practical=20
purposes. I suggest that you keep a note of the errors for a day =
or two.=20
They are often very large.       =
You can=20
buy a radio corrected crystal clock for less than \$20. They are =
very=20
useful and are accurate to 20 mS. They update every hour.=20
You can also visit=20
http://nist.time.gov/ and cross check on-line, but do watch out =
for=20
transient data delays.
I would like =
to try and=20
compare events elsewhere in the world / country to my sensor. At =
this=20
site I can see various locations.The =
question.    If I=20
know in  when in UTC an event occurred, and where.. how do =
I=20
convert that to a UTC time when the event would arrive at my =
location,=20
if ever.In other words how ho long does it take to get=20
here??   =
Y=20
ou can calculate arrival time using http://neic.usgs.gov/nei=
s/travel_times/=20
=20
and=20
also download tables and charts to measure the distance from the P =
to S=20
delay time.      =20
Regards,       Chris=20
Chapman
```