Anybody know the actual mathematical odds of experiencing a hurricane and an earthquake in the same week?

Not really, but I can take a pass at it. For simplicity, I’ll assume we’re talking about an earthquake of magnitude 5 or more (since quakes below that magnitude are often not that noticeable). According to the USGS, there are an average of 1469 earthquakes of magnitude 5+ per year, globally. We’ll call it 1500 to make the math easy.

According to the University of Colorado’s NCAR, there have been an average of 8 hurricanes per year in the last decade or so, a number that has been rising. Hurricanes are seasonal, with the official season stretching for 6 months (26 weeks), though hurricanes can arrive out of season. Hurricanes can remain at hurricane strength for a matter of hours, or can persist for as long as 31 days, so we’ll assume a 2 week window.

The probability of one or more hurricanes existing during any given 2 week stretch of hurricane season is about 45% (this takes into account the likelihood of two hurricanes existing simultaneously). During that 2 week period, you’d expect an average of 56 earthquakes of magnitude 5 or more, meaning that it’s essentially guaranteed that such an earthquake will strike somewhere on earth during the duration of a hurricane.

Calculating the odds of an earthquake and a hurricane striking the same place gets much trickier, because the odds of a given spot experiencing an earthquake and the odds of that same spot experiencing a hurricane are vary from place to place. In a normal year, Ft. Myers, FL, has a 16% chance of getting hit by a hurricane, while New York has about a 4.4% chance. The New York area has experienced 7 damaging earthquakes in the last 300 years, annual probability of 2.3% (0.045% per week).

Redoing the math, that works out to a probability of a hurricane and an earthquake occurring in the same week in the New York area (during hurricane season) of 0.00015%, odds of about 1:1,500,000.