Fate of Slabs

Invert P waves for 3-D mantle structure

10 million travel times: ISC, NEIC, temporary arrays0.5 million earthquakesRay theory & 3-D sensitivity kernelsModel norm and gradient regularization

Li, van der Hilst, Engdahl, and Burdick, 2008; G3

1-4 Cocos plate: complex structures into lower mantle

6-9 Nazca and Farallon plates subduct into lower mantle

10 South Sandwich Islands

Steep upper mantle slabs (Kuril, Mariana) subduct below 660

Shallow-dip(Japan, Izu-Bonin) and young slabs (Ryukyu) stagnate in transition zone

• Deep subduction: Central America, Indochina, segments of NW and SW Pacific

• Stagnation of slab fragments (400-1000 km) N Philippine Sea plate and SE Asia, Mediterranean, parts of Tonga

(Kellogg et al. 1999)

South America