The role of fluids in earthquake generation in the 2009 Mw6.3 L'Aquila, Italy, earthquake and its foreshocks: Figure 1.

1055 The 2009 L’Aquila earthquake in Italy, and its foreshock sequence, has been in the news lately for all the wrong reasons (Nosengo, 2010), but this month two papers in Geology use the sequence to suggest new breakthroughs in science: they provide strong evidence that high fl uid pressure contributed to the rupture. Fluids and their movement have been increasingly implicated in earthquake generation, yet few studies have quantifi ed the relationship for individual earthquake sequences. In this issue of Geology, Terakawa et al. (2010, p. 995) present a new method of mapping fl uid pressure from focal mechanisms, and use the entire suite of earthquakes to show that fl uids were highly overpressured near the foreshocks and subsequent mainshock. Lucente et al. (2010, p. 1015) show that earthquakes in the early part of the foreshock sequence yielded different measures of the ratio of compressional-to-shear velocity