Small repeating earthquake activity, interplate quasi‐static slip, and interplate coupling in the Hyuga‐nada, southwestern Japan subduction zone

Abstract

[1] Small repeating earthquake (RE) analysis is a useful method for estimating interplate quasi-static slip, which is a good indicator of interplate coupling. We detected 170 continual-type interplate RE groups and then estimated the spatial variation in quasi-static slip in the Hyuga-nada over the past 17 years. The RE activity in this region has different characteristics compared with that in the northeast Japan subduction zone, presumably reflecting differences in the subduction properties. Our results revealed that interplate coupling spatially changes along the trench-axis and dip-direction-a phenomenon that cannot be resolved by land-based Global Positioning System (GPS) analysis. By comparing seismicity, the low-slip-rate areas correspond with the location of hypocenters and asperities for largeand moderate-sized interplate earthquakes, suggesting strong interplate coupling at these sites. These results indicate that the slip rate distribution estimated from RE activity is reliable and useful for assessing the potential of future large earthquakes. Citation: Yamashita, Y., H. Shimizu, and K. Goto (2012), Small repeating earthquake activity, interplate quasi-static slip, and interplate coupling in the Hyuga-nada, southwestern Japan subduction zone, Geophys. Res. Lett., 39, L08304,

Quasi‐periodic slow slip events in the afterslip area of the 1996 Hyuga‐nada earthquakes, Japan

“…The estimated backslip model closely reproduces the observations as shown in Figure a. It has been reported that the asperity areas of the past large Hyuga‐nada earthquakes are strongly coupled (see Figure ) on the basis of on a study of repeating earthquakes [ Yamashita et al ., ].…”

Triggering of repeating earthquakes in central California

“…Repeating earthquakes have been identified near Parkfield, CA [ Nadeau et al ., ; Lengline and Marsan , ; Rubinstein et al ., ; Chen et al ., ; Turner et al ., ], in numerous other regions [e.g., Peng and Ben‐Zion , ; Schaff and Richards , ; Yamashita et al ., ; Yu and Wen , ; Yu , ] and in the laboratory [ Savage and Marone , ; Rubinstein et al ., ; Johnson et al ., ]. A repeating earthquake family is a group of events with similar waveforms, epicenters, and magnitudes, resulting from repeated ruptures of the same patch of fault or nearly the same patch [ Nadeau and Johnson , ].…”

The Long Recurrence Intervals of Small Repeating Earthquakes May Be Due to the Slow Slip Rates of Small Fault Strands

“…They are recognized via their similar waveforms and consistent rupture area and are often used to track the slip rate of the creeping faults that host them (e.g., Igarashi et al, 2003;Materna et al, 2018;Meng et al, 2015;Nadeau & Johnson, 1998;Nadeau & McEvilly, 1999;Schmittbuhl et al, 2016;Uchida et al, 2016). Repeaters have been used to track slip rates on strike-slip faults (e.g., Lengliné & Marsan, 2009;Nadeau & Johnson, 1998;Peng & Ben-Zion, 2005;Schaff et al, 1998;Schmittbuhl et al, 2016;Templeton et al, 2008), subduction zones (e.g., Dominguez et al, 2016;Hatakeyama et al, 2017;Igarashi et al, 2003;Yamashita et al, 2012;Ye et al, 2014;Yu, 2013;Zhang et al, 2008), thrust faults (e.g., Chen et al, 2008), and triple junctions (e.g., Chen & McGuire, 2016;Materna et al, 2018), but the physics that controls repeaters' recurrence rates remains poorly understood.…”