• journal_title：Geology
• Contributor：J. Casey Moore ; Demian Saffer
• Publisher：Geological Society of America
• Date：2001-
• Format：text/html
• Language：en
• Identifier：10.1130/0091-7613(2001)029<0183:ULOTSZ>2.0.CO;2
• journal_abbrev：Geology
• issn：0091-7613
• volume：29
• issue：2
• firstpage：183

Off southwest Japan the seaward limit of coseismic displacement (or updip limit of the seismogenic zone) of the 1946 M_w 8.3 thrust earthquake reaches to 4 km depth and ∼40 km landward of the trench. This limit coincides with the estimated location of the 150 °C isotherm, and has been linked to changes in physical properties associated with the smectite to illite clay-mineral transition. Here we show that this limit correlates with a suite of diagenetic to low-grade metamorphic processes characterized by (1) declining fluid production and decreasing fluid pressure ratio (λ^*) and (2) active clay, carbonate, and zeolite cementation and the transition to pressure solution and quartz cementation. These diagenetic to low-grade metamorphic changes cause the onset of velocity weakening during thrust faulting, an increase in effective stress, and strengthening of the hanging wall, which together combine to produce recordable earthquakes.