Earthquake Seismology: Magnitudes, Energy, Epicentres & Recurrence

What you'll build

What you will be able to do

Each lab ends with a concrete result that you build yourself and the checker confirms, cell by cell.

• Calculate the seismic moment of six fault ruptures from area, slip and rigidity, turn it into moment magnitude Mw and go back from a magnitude to the moment.
• Turn eight magnitudes into radiated energy and TNT equivalents, compare them with a reference event, and see the difference between the energy ratio and the amplitude ratio.
• Calculate P and S travel times for six distances, chart the travel-time curves, and turn four stations' S−P intervals into distances to the earthquake.
• Turn three stations' S−P intervals into distances, test 20 candidate epicentres on a grid by their distance misfit, and let INDEX and MATCH pick the best one.
• Take the log of a 20-year catalogue's cumulative counts, fit the a- and b-values with INTERCEPT and SLOPE, chart the relation with a trendline and extrapolate to M 6.
• Turn the regional Gutenberg–Richter values into annual rates and recurrence intervals, calculate the Poisson chance of at least one event in 50 years, and derive the classic 475-year return period.
• Apply the modified Omori law to a fictional M 6.4 mainshock: the aftershock rate on each of the first ten days, the expected count per day by integration, the 10-day total and the day the rate drops below 10 per day.
• Calculate the hypocentral distance and an illustrative intensity for eight towns, translate it into perceived shaking with an approximate VLOOKUP, and count the towns with strong shaking.