# Question about timing of traces from Raspberry Shake	data

**URL:** <https://discourse.obspy.org/t/question-about-timing-of-traces-from-raspberry-shake-data/849>\
**Category:** Users Mailing List Archive\
**Tags:** archive\
**Created:** [July 30, 2019, 8:02pm UTC](https://discourse.obspy.org/t/question-about-timing-of-traces-from-raspberry-shake-data/849 "2019-07-30T20:02:56Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![kafka](https://discourse.obspy.org/letter_avatar_proxy/v4/letter/k/3d9bf3/32.png) [@kafka](https://discourse.obspy.org/u/kafka)\
**Post date:** [July 30, 2019, 8:02pm UTC](https://discourse.obspy.org/t/question-about-timing-of-traces-from-raspberry-shake-data/849/1 "2019-07-30T20:02:56Z")

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Hi,

I am new to learning ObsPy and to joining the ObsPy community, so let me know if I am writing this question to the wrong place. If I am, please direct me to the right place…

Here’s my question: I am trying to plot traces of two quarry blasts recorded by a Raspberry Shake seismograph in Vermont (see attached notebook), and plot them so that the time axis is the same for both (15 sec). But, when I try to do that, the times are not the same as what I thought I set them up to be (see attached). For example:

- The starttime requested for Trace 1 is 2019-07-24 13:30:36, but the starttime shown in the print of the Trace Steam is 2019-07-24T13:30:35.537000Z.

- The starttime requested for Trace 2 is 2019-07-25 15:00:28, but the starttime shown in the print of the Trace Steam is 2019-07-25T15:00:27.627000Z.

Why are these times different? Can I force them both to be 15 sec long?

Also, it seems to me that what I am trying to do would be a common thing that others in this community might have already done. If yes, please direct me to any things that are already set up that you think I should be looking at RE what I am trying to do.

Thanks,

~ Alan Kafka

[RS\_Notebook.ipynb](https://discourse.obspy.org/uploads/short-url/suO4EEOniUrAAOPIMToP3hzjKKe.ipynb) (200 KB)

 ![Screen Shot 2019-07-30 at 10.49.25 AM.png](https://discourse.obspy.org/uploads/default/original/1X/413f36eab9ecac6ac7615cf2ebd52fc0e3be7328.png)

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**Author:** ![megies](https://discourse.obspy.org/user_avatar/discourse.obspy.org/megies/32/9_2.png) [@megies](https://discourse.obspy.org/u/megies)\
**Post date:** [August 12, 2019, 9:21am UTC](https://discourse.obspy.org/t/question-about-timing-of-traces-from-raspberry-shake-data/849/2 "2019-08-12T09:21:40Z")

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See [Fix trimming waveforms after fetching from FDSN Client by LMurrayBergquist · Pull Request #2298 · obspy/obspy · GitHub](https://github.com/obspy/obspy/pull/2298), fixed in master. For now  
you can just add a trim call after fetching the data

st.trim(starttime, endtime)

best,  
Tobias