RECORDED EVENT 01
Place one epicenter marker inside every station’s distance band.
A band, not an exact circle. Rounded S−P timings describe a range of distances. The lower boundary counts; the upper boundary does not.
Move the marker into all the distance bands. Any valid grid point is accepted.
An invented event has already been recorded. Use the stations’ rounded S−P arrival differences to find a possible epicenter on the whole-kilometre grid, 0–16 km east and north.
The slower S wave arrives after P. In this model, distance = 6 × S−P delay. The readings are rounded, so each one gives a distance band.
Tap a point on either view, enter coordinates and Set marker, or use the direction buttons. Both views show the same location.
Lower edges are included; upper edges are excluded. Any grid point satisfying all stations is accepted. No hidden exact location is required.
3 stars: no unsuccessful checks or hints. 2 stars: up to two unsuccessful checks, no hints. 1 star: every completed record. Undo and reset preserve check and hint history. Best stars save on this device when storage is available.
Differences between P- and S-wave arrivals help seismologists estimate how far a source is from a station. Combining stations constrains its location. Real earthquake location also depends on depth, origin time and a model of wave speeds through Earth.
Seismote uses a flat, zero-depth, uniform-speed teaching model: vP = 6 km/s and vS = 3 km/s. For distance d, Δt = d/3 − d/6 = d/6, so d = 6Δt. These speeds and simplifications define this puzzle, not a universal real-world distance rule.
This locates a possible already recorded fictional event. It does not predict earthquakes or estimate magnitude. Ring widths represent rounding of the stated S−P interval, not a full real-world uncertainty model.
USGS: The Science of Earthquakes and How do seismologists locate an earthquake?. Numeric records are authored fictional game data.
Original Blender mentor, station board and marker props. Sound effects: Kenney Interface Sounds (CC0). Runtime: Three.js (MIT). Fonts: Space Grotesk and IBM Plex Mono, Google Fonts.
60 records in each of three courses, 180 total. Every record has at least one valid grid point.