Quick Quake vs Pocket Seismograph

Rapid earthquake location and magnitude verification has never been easier. Quick Quake is also a great educational tool – simply use the demo data to see how P (primary) and S (secondary) waves are used to determine the location of an earthquake. Quick Quake is an earthquake data analysis tool that allows users to quickly determine the epicentre and magnitude of an earthquake by simply picking a P wave and S wave arrival from a single seismograph, then moving the epicentre around a map until the seismograms from the other stations line up in time. The Seismology Research Centre has developed Quick Quake so that users of the Quake Server seismic observatory data management system can quickly verify the automatic event notifications that Quake Server sends out by email. The traditional method of locating earthquakes can take anywhere from 10-20 minutes, but with Quick Quake you can verify or refine the automatic eqServer location and magnitude in less than a minute. How to use Quick Quake with the demo data: • Select which station you wish to use to pick a P and S wave (the “key site”) and hit the target icon • Drag the P (primary wave) marker to the right until it aligns with the first signal that you can see above the background noise • Drag the S (secondary wave) marker to the left until it aligns with the significant increase in signal level (see the screenshots as a guide) • Pinch to zoom the time and amplitude scale if you need better resolution • Continue to the locating screen, where you can drag the target around the circle until the waveforms on the left of the screen roughly align with the P and S travel time guide lines It’s that simple. The solution should work no matter which station you choose, but the closer the station the easier the P and S wave arrival times will be to pick. If you have an Quake Server, just log in using your credentials and the server's IP address or domain name, then you can browse through recent (and past) automatic events and proceed as above. On the “Select a Key Site” screen, you can defer stations from your calculations using a left-swipe, or restore them with a right-swipe. You can also sort your stations in order of distance from the selected “key site”. On the “Locate Event” screen there is are options to adjust the P-wave and S-wave travel velocities to suit your local conditions, as well as the depth of the earthquake. The iPad version shows quick-adjustment buttons, and iPhone and iPad versions include three presets for P and S velocity “models” - now with a customisable magnitude formula. Contact the Seismology Research Centre to learn more about seismographs, Quake Server, and earthquake monitoring networks. Remember to follow the SRC on Facebook and Twitter.

See how hard a surface is shaking, and at what frequency. Pocket Seismograph reads your iPhone's accelerometer at 100 Hz, draws the vibration live, and names the strongest frequency it can find in it. WHAT YOU GET - Dominant frequency in Hz, with a full spectrum chart behind it - Live trace with NOW, MAX, AVG and RMS, as magnitude or full XYZ - Rotation-speed readout in rpm, offered as a hypothesis when the reading looks like a rotating part - Estimated felt intensity and estimated peak ground velocity - Three processing modes: Raw, Stable and Vibration - Sessions you can name, tag, search and reopen - CSV export through the system save dialog, with locale-aware profiles - Calibration wizard that measures your own device's noise floor - Works offline. No account, no sign-in. GREAT FOR - A washing machine that walks across the floor. A spin cycle sits around 17 to 27 Hz, and the app names it. - HVAC units and fans: read the running frequency, then the rpm it implies. - Floors, stairs and beams that move when someone walks past. - Construction, traffic or machinery you want recorded with a timestamp. - Feeling a tremor and wanting the next one captured. HOW IT WORKS 1. Put the phone flat on the surface, screen up. 2. Press Start. Watch the trace and the frequency card. 3. Save the session, add a note, export CSV when you need to show someone. WHAT IT WILL NOT DO Frequency analysis reads reliably from about 1 Hz to 40 Hz, and only indicatively up to roughly 50 Hz. Vibration faster than half the sampling rate does not simply disappear, it folds back and can appear as a false low-frequency line. Amplitude is indicative: the case, how firmly the phone rests on the surface, and filtering inside the sensor itself all color the number. The frequency is the more trustworthy half of the reading. When nothing stands clearly above the noise, the app says "No clear frequency" rather than inventing one. That is the correct reading for a phone lying still on a desk. This is not a certified seismic instrument and it is not calibrated for legal evidence. It is not a medical or diagnostic device. It sends no seismic alerts, so for early warnings use your country's official system. It cannot see the 60 Hz to 500 Hz range where bearing and gear features live, so finding nothing here says nothing about them. Available in 49 languages. Built by an independent developer who thinks a measurement tool should tell you when it does not know. If it is useful to you, a review is the best thanks.