Rewriting the book on Earthquake Locations
Ethan Coon
(APAM)
Felix Waldhauser (LDEO)
Day One
• • • The science: Earthquake relocation The math: Deriving a linear system hypoDD: an algorithm for relocation
Day Two
• • • Solving the linear system Results and scaling Future work
hypoDD Algorithm
• •
•
Read in initial location data (initial guesses) Form cross-correlations for available pairs of waveforms
Use Clustering algorithm to form graph of earthquake pairs
•
•
Form matrix of the arrival time derivatives (simple model)
Compute weights based on measurement quality and distance between events Linear solve for changes in earthquake locations
~ 20 iterations for convergence with changing weights
•
~ 80% of clock time (on system of ~ 1k events)
PETSC !