<P> A study published in 2016 suggested a new parameter to determine a subduction zone's ability to generate mega-earthquakes . By examining subduction zone geometry and comparing the degree of curvature of the subducting plates in great historical earthquakes such as the 2004 Sumatra - Andaman and the 2011 Tōhoku earthquake, Bletery et al. determined that the magnitude of earthquakes in subduction zones is inversely proportional to the degree of the fault's curvature, meaning that "the flatter the contact between the two plates, the more likely it is that mega-earthquakes will occur ." </P> <P> Outer rise earthquakes occur when normal faults oceanward of the subduction zone are activated by flexture of the plate as it bends into the subduction zone . The 2009 Samoa earthquake is an example of this type of event . Displacement of the sea floor caused by this event generated a six - meter tsunami in nearby Samoa . </P> <P> Anomalously deep events are a characteristic of subduction zones, which produce the deepest quakes on the planet . Earthquakes are generally restricted to the shallow, brittle parts of the crust, generally at depths of less than twenty kilometers . However, in subduction zones, quakes occur at depths as great as seven hundred kilometers . These quakes define inclined zones of seismicity known as Wadati--Benioff zones, after the scientists who discovered them, which trace the descending lithosphere . Seismic tomography has helped detect subducted lithosphere, slabs, deep in the mantle where there are no earthquakes . About 100 slabs have been described in terms of depth and their timing and location of subduction . Some subducted slabs seem to have difficulty to penetrate the major discontinuity in the mantle, marking the boundary between the upper mantle and lower mantle, that lies at a depth of about 670 kilometers . Other subducted oceanic plates can penetrate all the way to the core - mantle boundary . The great seismic discontinuities in the mantle, at 410 and 670 kilometer depth, are disrupted by the descent of cold slabs in deep subduction zones . </P> <Table> <Tr> <Td> </Td> <Td> This section needs expansion . You can help by adding to it . (June 2010) </Td> </Tr> </Table>

Which of the following are linked to the process of subduction