Raspberry Shake iOS App - Clarifications needed

Living in a suburban setting in an aseismic area, my Shakenet is used to work out whether Canadian Pacific trains to heading to the continental divide are loaded with raw material for export into the Pacific Basin, or heading down to the Prairies with containers full of goods destined for our ubiquitous dollar stores. Thus in order to see quakes, I’ve migrated to the amateur-friendly tools on the iOS app, and I need help interpreting what I am seeing.

Q1: When I open an Event, I see a waveform, highlighted with P & S wave flags at time-P(tP) & time-S (tS). Am I correct in assuming these markers are best-guess extrapolations of the expected arrivals at that station, OR when do they represent when the event happened at the epicentre, and I’m to look to see & guess when the wave arrived at the station in question?

Q2: Given my seismically quiet location, I need to seek events up to 5000 km away. Thus the S-wave is forecast to arrive c. 3 minutes later (tS) but the UTC time scale appears fixed at 3 minutes, featuring the P-wave c. 30 seconds in from the LHS. Could the UTC timescale be self-adjusting so that the scale reflects from tP-30 seconds to tS+30 seconds in a future version?

Q3: As I’m temporarily using an old 2G/3G cellular modem attached to my Shake which is routinely affected by ebbing & flowing cell service, I get frequent, albeit brief timeouts. When that happens between tP & tS, my Frequency graphic is cut short at the beginning of the timeout. As I’m currently relying on 55 year old seismology training from the dawn of the plate tectonics era, I haven’t dug deeply to try and work out why the Frequency image cannot leapfrog over a brief timeout. Thoughts?

Q4: Appreciating the purpose of the iOS app, would there be any advantage to allowing the viewer to scroll on the Waveform graphic past tS, and have the Frequency graphic follow along to look for surface waves (Rayleigh & Love) or secondary events (rockfalls, avalanches, etc.)

Hello MRT1953,

Let’s see, regarding your questions:

Q1 - These are computed estimations of when the waves should arrive at your seismometer based on the seismic models. At the moment, the code is accurate for medium distance to far-away events, while it is not so precise for close events. This will be fixed in a future release of our software.

Q2 & Q4 - I will be answering these two together, since they are related to a new feature request. Thank you for these suggestions, which are always appreciated! As of now, it is possible to see beyond the ~3 minutes event window by going to the 24hrs plot screen, where everything in the last day can be observed and filtered as needed. Again, an eventual future release of the app will contain your requests, once they will have been coded, tested, and validated.

Q3 - Thank you for reporting this issue to us. I have forwarded it to our App team and they will take a look at it. They will have to check what would be involved to make the frequency domain plots more gracefully handle gaps in the time domain.

Thank you again for all your observations.