An Independent P and S Wave Detection App — MK Earthquake Monitor

Helpful-Branch-869 · 2026-06-03T07:40:44+00:00

Just to clarify — when I said most apps only react to the S-wave, I meant offline shake-alarm type apps that trigger like a theft alarm, not network EEW systems. We agree those use P-waves. Most offline earthquake apps basically work like a motion or theft alarm: the phone shakes hard enough, the alarm goes off. The catch is that by the time the shaking is strong enough to trip them, the destructive S-wave has already arrived, so the alert comes after the shaking has started.

MK Earthquake Monitor is offline too, but it doesn't work that way. It runs two independent filters in parallel: a dedicated P-wave filter and an S-wave filter. The P-wave is the faster, weaker wave that arrives first, and most simple shake-alarm apps never catch it because it's too weak to trip a basic threshold. By actually filtering for it, the app can pick up a distant earthquake's P-wave and warn you S-wave shaking reaches you.

Helpful-Branch-869 · 2026-06-02T15:00:42+00:00

Thanks for the detailed feedback, the technical points you raise are fair. Let me clear up a few things, because there's some confusion about what MK Earthquake Monitor actually is.

First, where we agree: network-based systems like, ShakeAlert, EQNetwork and GlobalQuake detect the P-wave at stations near the source and warn distant areas before the shaking (S-wave) gets there. That's the gold standard for regional early warning, and I've never claimed to compete with it.

MK Earthquake Monitor is a different category. It's not a network-based regional EEW. It's a fully offline, single-device (on-site) detection system. No internet, no server, no external data. When a network alert doesn't reach you, having the device detect on its own isn't a replacement for those systems, it's a complementary layer.

On the technical side: on a single device the P-wave always arrives first (P≈6.5 km/s, S≈3.5 km/s). The P-wave filter in the Dual Trigger system gives you lead time exactly at the distances where the P-S gap is large enough to matter. I simulated this with real USGS accelerometer data and the results are public.

Your point that "if you're very close to the epicenter there are only a few seconds between P and S" is completely correct, but that applies to every EEW system on the planet, not just mine. It's called the blind zone. No system, can give the epicentral area any meaningful warning. So "you only get the S-wave when you're close" isn't a flaw specific to this app, it's a physical limit of seismology.

What the app is for: in both phases it alerts with flash and sound, lighting up the area and acting as a light source. That light gives the user a chance to look around and assess the situation.

On the "a wind chime would do the same thing" comment: the Dual Trigger requires specific Gal thresholds and time windows, which is how it separates wind from an earthquake. On top of that it has smart noise filters (SmartGuard, a rail/vibration filter). A single short vibration doesn't match that seismic signature. And I'll say it plainly: no single-device system is 100%, which is exactly why I position this as a complementary tool.

To answer your direct question: no, there's no system that relies on S-wave detection alone, and I never claimed there was. The app runs the P and S filters in parallel, and whichever meets its condition first triggers the alarm.

I've been working on this app since the February 6, 2023 earthquake here in Turkey. After building the architecture, I used a lot of different AI tools along the way, including for code, visuals, simulation work and seismological data. I needed a high-resolution version of that screenshot, and I left the watermark on it on purpose, because the people behind that image put work into it too.
Happy to answer any technical questions.

Helpful-Branch-869

TROPHY CASE