OMSI Science Pub Eugene: Large Earthquakes

When Do Large Earthquakes Know They’ll Be Large?

With Diego Melgar, PhD, Assistant Professor of Geophysics at the University of Oregon

Large earthquakes (magnitude 8 to 9) are not how they’re portrayed on TV. They’re not singular point-like events that happen instantly. In reality, a large earthquake breaks a fault that can be several hundred miles long and can take as long as 5 minutes to rupture completely. So a key question is when, within this minutes-long process does, a magnitude 9 look different from a magnitude 8? Is it at its birth? Perhaps in the first few seconds the events look different, or perhaps there simply isn’t any way to tell and we must simply wait until the rupture is finished before being able to know the magnitude. This is the question of determinism in earthquake rupture and it directly impacts real-world applications like earthquake early warning. If there are tell-tale signs in the first few seconds of an earthquake then the warnings will be delivered that much quicker.

In this talk seismologist Diego Melgar will explore these issues and show how there is evidence in recent large earthquakes that within about 15 seconds it should be possible to discern the large from the very large. 

Diego Melgar is Assistant Professor of Geophysics at the Department of Earth Sciences at the University of Oregon. Diego graduated from the Scripps Institution of Oceanography in 2014 with a Ph.D. in geophysics. There he worked on how to use GPS for seismology. He also spent three years at the University of California Berkeley’s SeismoLab working on early warning systems. At the UO his research focuses on large earthquakes. He works on the physics of the rupture process and also researches the hazards associated with these large events. He works on tsunami modeling and coastal impacts as well as studying how strong shaking is generated. Diego continues to research how to best build early warning systems to abate the societal impact of these hazards.

November 14, 2019 | 6:30-8:30PM; Doors open @ 5PM | $5 Suggested Donation

Science Pub Eugene is a monthly event that is open to anyone and everyone. No RSVP or scientific background required. Just bring your curiosity, sense of humor, and appetite for food, drinks, and knowledge! For more information or to sign up for our mailing list, email: sciencepub@omsi.edu.