Holocene Raised Coral Reefs of Kikai-Jima (Ryukyu Islands)

Ôta, Yôko; Machida, Hiroshi; Hori, Nobuyuki; Konishi, Kenji; Omura, Akio

doi:10.4157/grj.51.109

Cited by 58 publications

(15 citation statements)

References 5 publications

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“…0 conclude that Holocene terraces are the result of paleoseismic uplifts because the Great Alaskan earthquake of 1964 produced the lowest terrace of the series. This approach contrasts with that presented for Kikai Island in the Ryukyu arc for several Holocene reef terraces occurring from sea level up to about 10 m altitude [Nakata et al, 1978;Ota et al, 1978]. Shimazaki and Nakata [1980] equated each terrace with a single coseismic uplift event even though there were no contemporary uplifts that supported this assertion.…”

Section: Determination Of the Precise Ages Of Uplift Eventscontrasting

confidence: 46%

Seismic recurrence intervals and timing of aseismic subduction inferred from emerged corals and reefs of the Central Vanuatu (New Hebrides) Frontal Arc

Taylor¹,

Edwards²,

Wasserburg³

et al. 1990

J. Geophys. Res.

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The recogmuon and dating of corals that have been killed by tectonic uplift allow us to date paleoseismic uplifts in the Vanuatu island arc. We recognize corals that record paleouplifts by their similarity to those known to have died during contemporary sudden uplifts and date them (1) by counting annual coral growth bands (only if f:rt of the coral is alive at the time of collection) or (2) by newly developed techniques for obtaining 0 Th ages by mass spectrometry. The mass spectrometric method produces isotopic ages with precisions of ±3 to ±9 years (20') in the 0-HlOO years B.P. The maximum uplift of 2.7 mm yr 1 occurs near a nest of small earthquakes. Both the earthquakes and rapid uplift suggest that interplate slip beneath south Malekula may be continuous, rather than episodic. Episodes of 0.35 m uplift would have to recur every 130 years to maintain the 2.7 mm yr· 1 uplift rate. In contrast, we find no evidence of interseismic vertical movements for the other three blocks. The most reasonable interpretation of these resuhs is that the seismic recurrence intervals and processes for accommodation of slip are quite different on adjacent arc segments. We have used the most widely accepted momentmagnitude relationship to evaluate the accumulated seismic slip caused by large earthquakes occurring since 1920. In all four arc segments this analysis suggests that the seismically radiated moments account for less than one-third to one-tenth of the slip associated with plate convergence. The similarity between the paleoseismic record of uplifts and the contemporary record of coseismic uplifts suggests that this analysis can be generalized to times before 1920. For the northern three segments of central Vanuatu, aseismic slip probably occurs in the same years as large earthquakes because the contemporary coral record records uplifts only in years having large historic earthquakes. This suggests that aseismic slip is not continuous and does not occur at rates which vary slowly over the course of the earthquake cycle. The soulh Santo segment may have the highest proportion of seismic slip because the mean recurrence interval of 51 years is shortest and the mean Holocene uplift rate of at least 5.5 mm yr· 1 is the fastest.

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Section: Determination Of the Precise Ages Of Uplift Eventscontrasting

confidence: 46%

Seismic recurrence intervals and timing of aseismic subduction inferred from emerged corals and reefs of the Central Vanuatu (New Hebrides) Frontal Arc

Taylor¹,

Edwards²,

Wasserburg³

et al. 1990

J. Geophys. Res.

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“…Specifically, the differentiation between TI and TII occurred over 130 years, suggesting that a 7-m vertical displacement was caused by one or more large earthquakes approximately 2400 years ago. In contrast, the vertical displacements of Holocene terraces at islands located near the Ryukyu Trench, such as Kikai Island (28°N, 130°E), are generally less than 5 m (Nakata et al, 1978;Ota et al, 1978).…”

Section: Tectonicsmentioning

confidence: 86%

“…The type of uplifts near Kodakara Island may have been different from that experienced in areas located near trench zones, such as Kikai in the Ryukyu Islands (Ota et al, 1978(Ota et al, , 2000Sugihara et al, 2003) and the Huon peninsula of Papua New Guinea (e.g., Ota and Chappell, 1996). Because Kodakara is located on an inner arc and near the Tokara strait in the NWP, the uplifts near Kodakara Island may have been caused by subduction and lateral faults in the Tokara Channel (Konishi, 1965;Kizaki, 1978) and the extent of the Okinawa Trough (Kawana, 2001).…”

Section: Tectonicsmentioning

confidence: 92%

Holocene reef-growth dynamics on Kodakara Island (29°N, 129°E) in the Northwest Pacific

et al. 2015

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“…On the other hand, the Tokara Channel does not correspond to the position with the maximum arc curvature and thus the relationship between the arc migration and the across-arc depressions is still unclear. Interestingly, the active uplifting of the arc crust has been happening at the Kikaijima Island located just south of the Tokara Channel (Ota et al 1978), resulting in a contrasting tectonic movement in a small area (Fig. 1).…”

Section: Geological Backgroundmentioning

confidence: 99%

Seismic evidence for arc segmentation, active magmatic intrusions and syn-rift fault system in the northern Ryukyu volcanic arc

Arai

Kodaira

Takahashi

et al. 2018

Earth Planets Space

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Tectonic and volcanic structures of the northern Ryukyu arc are investigated on the basis of multichannel seismic (MCS) reflection data. The study area forms an active volcanic front in parallel to the non-volcanic island chain in the eastern margin of the Eurasian plate and has been undergoing regional extension on its back-arc side. We carried out a MCS reflection experiment along two across-arc lines, and one of the profiles was laid out across the Tokara Channel, a linear bathymetric depression which demarcates the northern and central Ryukyu arcs. The reflection image reveals that beneath this topographic valley there exists a ~ 3-km-deep sedimentary basin atop the arc crust, suggesting that the arc segment boundary was formed by rapid and focused subsidence of the arc crust driven by the arc-parallel extension. Around the volcanic front, magmatic conduits represented by tubular transparent bodies in the reflection images are well developed within the shallow sediments and some of them are accompanied by small fragments of dipping seismic reflectors indicating intruded sills at their bottoms. The spatial distribution of the conduits may suggest that the arc volcanism has multiple active outlets on the seafloor which bifurcate at crustal depths and/or that the location of the volcanic front has been migrating trenchward over time. Further distant from the volcanic front toward the back-arc (> 30 km away), these volcanic features vanish, and alternatively wide rift basins become predominant where rapid transitions from normal-fault-dominant regions to strike-slip-fault-dominant regions occur. This spatial variation in faulting patterns indicates complex stress regimes associated with arc/back-arc rifting in the northern Okinawa Trough.

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Holocene Raised Coral Reefs of Kikai-Jima (Ryukyu Islands)

Cited by 58 publications

References 5 publications

Seismic recurrence intervals and timing of aseismic subduction inferred from emerged corals and reefs of the Central Vanuatu (New Hebrides) Frontal Arc

Seismic recurrence intervals and timing of aseismic subduction inferred from emerged corals and reefs of the Central Vanuatu (New Hebrides) Frontal Arc

Holocene reef-growth dynamics on Kodakara Island (29°N, 129°E) in the Northwest Pacific

Seismic evidence for arc segmentation, active magmatic intrusions and syn-rift fault system in the northern Ryukyu volcanic arc

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