The 2004 sequence of triggered earthquakes off the Kii peninsula, Japan

Park, Sun-Cheon; Mori, Jim

doi:10.1186/bf03352569

Cited by 22 publications

(21 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We therefore propose the existence of a fault in the oceanic lithosphere. A fault such as this is consistent with the mechanism of the fault that generated the mainshock of the 2004 earthquakes, which also dips to the south (e.g., Hashimoto et al, 2005;Park and Mori, 2005;Bai et al, 2007). Seismic activity farther down-dip along the subducting PHS is very much lower.…”

Section: Seismic Activity Along the Nankai Troughmentioning

confidence: 59%

“…12) and extend to very shallow depths in the oceanic crust. Although the fault that generated the foreshock of the 2004 event dips to the north (e.g., Park and Mori, 2005;Bai et al, 2007), the hypocentral plane in Figure 12 dips to the northeast and does not therefore represent that fault. In this region, Tsuji et al (2013) identified northeast-dipping intraoceanic thrusts that are consistent with the hypocenter distribution we have defined.…”

Section: Seismic Activity Along the Nankai Troughmentioning

confidence: 96%

See 1 more Smart Citation

Hypocenters in the Nankai Trough Determined by Using Data from Both Ocean‐Bottom and Land Seismic Networks and a 3D Velocity Structure Model: Implications for Seismotectonic Activity

Nakamura¹,

Kaneda²

2015

Bulletin of the Seismological Society of America

View full text Add to dashboard Cite

We investigated the hypocenter distribution along the Nankai trough off the Kii Peninsula, Japan, by using data from both ocean-bottom and land-based seismic networks. Because seismic velocity structures differ greatly below land and ocean, we used a 3D velocity model based on a structural model of the Philippine Sea plate (PHS), which provides much more accurate estimations of source locations than 1D velocity models derived from either onshore or ocean-bottom seismic data alone, especially for sources between the coast and the trough axis. We identified intensive seismic activity below the axis of the Nankai trough, which we interpreted to be aftershocks of the 2004 Off the Kii Peninsula earthquakes (M JMA 7.1, 7.4, and 6.5), but found much less seismic activity along the subducting PHS. The earthquake sources below the trough axis lie on dipping planes within the PHS, from which we inferred that a fracture zone is developing within the PHS. Our estimated focal mechanisms for these earthquakes showed that their P axes were oriented north-south to northeast-southwest, similar to those of the 2004 events, which were rotated clockwise by 45°-90°from the northwest-southeast direction of convergence between the PHS and the Eurasian plates. We consider that the fracture zone represents a boundary between the PHS and the Izu microplate, which are converging in a north-south direction, and that the 2004 earthquakes and subsequent seismic activity were caused by the collision of these plates.

show abstract

Section: Seismic Activity Along the Nankai Troughmentioning

confidence: 59%

Section: Seismic Activity Along the Nankai Troughmentioning

confidence: 96%

Hypocenters in the Nankai Trough Determined by Using Data from Both Ocean‐Bottom and Land Seismic Networks and a 3D Velocity Structure Model: Implications for Seismotectonic Activity

Nakamura¹,

Kaneda²

2015

Bulletin of the Seismological Society of America

View full text Add to dashboard Cite

show abstract

“…8(a)). The M w =7.5 mainshock occurred about 5 h after the foreshock on a multiple faulting with primarily two different fault planes: a northwest-tending strike-slip fault plane and a south-dipping reverse fault plane (Miyoshi and Ishibashi, 2005;Park and Mori, 2005;Satake et al, 2005;Yagi, 2005). After the mainshock, earthquakes extended in both the northwest and southwest directions from the location of the mainshock (Fig.…”

Section: Resultsmentioning

confidence: 99%

An improved double-difference earthquake location algorithm using s P phases: application to the foreshock and aftershock sequences of the 2004 earthquake offshore of the Kii peninsula, Japan (Mw=7.5)

et al. 2006

View full text Add to dashboard Cite

We have used s P phases to improve the hypocentral locations of the earthquakes that occurred offshore southeast of the Kii peninsula in association with the M w =7.5 mainshock on September 5, 2004. The earthquakes were more than 100 km from the onshore seismic network and, thus, their focal depths were poorly constrained. The s P phases were recorded about 7-11 s after the initial P phases, with both phases having almost the same apparent velocities. The computation of ray-paths revealed that the arrival times of the later s P phases are sensitive to focal depths. We have recalculated the hypocenters and origin times for 36 events with more than six s P phase identifications on seismograms recorded at the High Sensitivity Seismograph Network by including s P phases in a double-difference earthquake location algorithm, which eliminates the errors introduced by crustal heterogeneity. The relocation results were then compared with those from the Japan Meteorological Agency based on traditional absolute location techniques. Key words: The 2004 earthquake offshore of the Kii peninsula, foreshock and aftershock sequences, improved double-difference earthquake location algorithm using s P phases, Philippine Sea plate.

show abstract

“…There have been some similar examples in regions of triggered seismicity where smaller “foreshocks” led to a larger triggered earthquake within hours to days. These include the M6.5 Big Bear event following the M7.4 Landers earthquake [ King et al , 1994], the M5.5 event following the M6.6 2000 western Tottori, Japan, earthquake [ Ohmi et al , 2002], the M7.4 event following the M7.1 2004 Kii Peninsula, Japan, earthquake [ Park and Mori , 2005]. …”

Section: Discussionmentioning

confidence: 99%

Triggering of earthquakes during the 2000 Papua New Guinea earthquake sequence

Park

Mori

2007

J. Geophys. Res.

Self Cite

View full text Add to dashboard Cite

A sequence of large earthquakes occurred in the New Britain/New Ireland region of Papua New Guinea in late 2000. The sequence started with a Mw 6.8 earthquake along the New Britain Trench on 29 October. About 20 days later a Mw 8.2 earthquake occurred in the New Ireland region on 16 November and produced large strike‐slip surface displacements and tsunamis. Following the Mw 8.2 event, two large earthquakes (Mw ∼ 7.5) occurred along the nearby New Britain Trench on 16 and 17 November. Furthermore, small triggered events were observed over a wide area outside of the rupture zones of the large earthquakes, with different focal mechanisms from those of the major events. There is likely some mechanism(s) that triggered this remarkable sequence, and we document the details of the spatial and temporal patterns of the events. We investigated if static stress changes can explain the initiation of the large earthquakes and also some groups of triggered smaller events. There are mixed results. The occurrences of the two M ∼ 7.5 major events may be explained by the static stress changes; however, there are also some earthquakes that are not consistent with triggering by static stress changes. There may be multiple mechanisms, including static and dynamic stress changes, that are needed to explain the complicated sequence of earthquakes.

show abstract

The 2004 sequence of triggered earthquakes off the Kii peninsula, Japan

Cited by 22 publications

References 12 publications

Hypocenters in the Nankai Trough Determined by Using Data from Both Ocean‐Bottom and Land Seismic Networks and a 3D Velocity Structure Model: Implications for Seismotectonic Activity

Hypocenters in the Nankai Trough Determined by Using Data from Both Ocean‐Bottom and Land Seismic Networks and a 3D Velocity Structure Model: Implications for Seismotectonic Activity

An improved double-difference earthquake location algorithm using s P phases: application to the foreshock and aftershock sequences of the 2004 earthquake offshore of the Kii peninsula, Japan (Mw=7.5)

Triggering of earthquakes during the 2000 Papua New Guinea earthquake sequence

Contact Info

Product

Resources

About