The 9/11 anniversary this week conjures up strong feelings and memories for nearly every American who saw events unfold on TV that day, or even worse, lived through it. For me, I remember it was just a month or less after I started my career as a staff geotechnical engineer at URS. I remember watching in horror at home as I got ready for work, and coming into the office where someone had tried to tune in the news on the crappy CRT TV we had in the conference room.
As others around the world are remembering that day as well, I came accross an interesting article about the work of seismologist Won-Young Kim from Columbia University’s Lamont-Doherty Earth Observatory and his team who pieced together the seismic record of the 9/11 attacks, even working with federal and local investigators to more precisely identify the time of impact of each plane on the Twin Towers as well as the moment of their collapse. The collapse of each tower generated a seismic signal comparable to a magnitude 2.1 and 2.3 earthquake. It’s a very interesting read.
Hat Tip: The Seismology Of 9/11 by David Bressan