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.)