Transient Uplift After a 17th-Century Earthquake Along the Kuril Subduction Zone

Fujiwara

et al. 2016

Earth-Science Reviews

Self Cite

Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACTThe Nankai-Suruga Trough, the subduction zone that lies immediately south of Japan's densely populated southern coastline, generates devastating great earthquakes (magnitude > 8) characterised by intense shaking, crustal deformation and tsunami generation. Forecasting the hazards associated with future earthquakes along this >700 km long fault requires a comprehensive understanding of past fault behaviour. While the region benefits from a long and detailed historical record, palaeoseismology has the potential to provide a longer-term perspective and additional crucial insights. In this paper, we summarise the current state of knowledge regarding geological evidence for past earthquakes and tsunamis along the Nankai-Suruga Trough. Incorporating literature originally published in both Japanese and English and enhancing available results with new age modelling approaches, we summarise and critically evaluate evidence from a wide variety of sources. Palaeoseismic evidence includes uplifted marine terraces and biota, marine and lacustrine turbidites, liquefaction features, subsided marshes and tsunami deposits in coastal lakes and lowlands. While 75 publications describe proposed evidence from more than 70 sites, only a limited number provide compelling, well-dated evidence. The best available records enable us to map the most likely rupture zones of twelve earthquakes that occurred during the historical period. This spatiotemporal compilation suggests that the AD 1707 earthquake ruptured almost the full length of the subduction zone and that earthquakes in AD 1361 and 684 may have been predecessors of similar magnitude. Intervening earthquakes were of lesser magnitude, highlighting the variability in rupture mode that characterises the Nankai-Suruga Trough. Intervals between ruptures of the same seismic segment range from less than 100 to more than 450 years during the historical period. Over longer timescales, palaeoseismic evidence suggests intervals between earthquakes ranging from 100 to 700 years, however these figures reflect a range of thresholds controlling the creation and preservation of evidence at any given site as well as the genuine intervals between earthquakes. At present, there is no geological data that suggest the occurrence of a larger magnitude earthquake than that experienced in AD 1707, however few studies have sought to establish the relative magnitudes of different earthquake and tsunami events along the Nankai-Suruga Trough. Alongside the lack of...

Section: The Eastern Nankai (B) Segmentmentioning

confidence: 99%

A systematic review of geological evidence for Holocene earthquakes and tsunamis along the Nankai-Suruga Trough, Japan

Fujiwara

et al. 2016

Earth-Science Reviews

Self Cite

“…Key contributions to practical earthquake hazard assessment include the identification of great (magnitude 8 or 9) earthquakes during the Holocene where there is no historical record (Atwater, 1987); earthquakes of substantially greater magnitude than directly observed (Minoura et al, 2001;Sawai et al, 2008); estimating recurrence intervals of great earthquakes (Atwater and HemphillHaley, 1997;Nelson et al, 1995); and defining different patterns of rupture along a subduction zone (Cisternas et al, 2005;Kelsey et al, 2002;Nelson et al, 2006;Sawai et al, 2004). Since publication of the seminal paper (Atwater, 1987), and widespread adoption of well-tested field and analytical methods (e.g.…”

Section: Introduction and Structure Of The Papermentioning

confidence: 99%

Detection limits of tidal-wetland sequences to identify variable rupture modes of megathrust earthquakes

Shennan

Quaternary Science Reviews

Barlow

2016

Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. earthquakes. We conclude that coastal paleoseismological studies benefit from a methodological framework that employs rigorous evaluation of five essential criteria and a sixth which may be very robust but only occur at some sites: 1 -lateral extent of peat-mud or mud-peat couplets with sharp contacts; 2 -suddenness of submergence or emergence, and replicated within each site; 3 -amount of vertical motion, quantified with 95% error terms and replicated within each site; 4 -syncroneity of submergence and emergence based on statistical age modelling; 5 -spatial pattern of submergence and emergence; 6 -possible additional evidence, such as evidence of a tsunami or liquefaction concurrent with submergence or emergence. We suggest that it is possible to consider detection limits as low as 0.1 to 0.2 m coseismic vertical change. Introduction and structure of the paperCoastal paleoseismology provides critical information that helps to improve understanding and modelling of seismic hazards, including associated tsunami, at all major subduction zones. Key contributions to practical earthquake hazard assessment include the identification of great (magnitude 8 or 9) earthquakes during the Holocene where there is no historical record (Atwater, 1987); earthquakes of substantially greater magnitude than directly observed (Minoura et al., 2001;Sawai et al., 2008); estimating recurrence intervals of great earthquakes (Atwater and HemphillHaley, 1997;Nelson et al., 1995); and defining different patterns of rupture along a subduction zone (Cisternas et al., 2005;Kelsey et al., 2002;Nelson et al., 2006;Sawai et al., 2004). Since publication of the seminal paper (Atwater, 1987), and widespread adoption of well-tested field and analytical methods (e.g. Atwater and Hemphill-Haley, 1997;Hayward et al., 2006;Kelsey, 2015;Nelson, 2015;Nelson et al., 1996;Witter, 2015) debate moved on to questions critical for hazard assessment, emergency planning and international building code design (Mueller et al., 2015;Wesson et al., 2007). Key questions include the extent of past great earthquake ruptures (a proxy for magnitude), the identification of the boundaries between rupture segments, the persistence of these boundaries over multiple earthquake cycles, recurrence intervals of great earthquakes in each segment, the role of aseismic slip, and whether segments of plate boundaries that are currently creeping can generate great earthquakes Goldfinger et al., 2012;Hayward et al., 2015;Kelsey et al., 2015;Mueller...

“…Sawai et al (2004), on the basis of diatom analysis, proposed that the deep slip occurred within decades after the 17th century earthquake. Because the giant fault is widest, the wavelength of crustal deformation is largest (Fig.…”

Section: Giant Fault Modelmentioning

confidence: 99%

Fault models of unusual tsunami in the 17th century along the Kuril trench

Satake

Nanayama²,

Yamaki³

2008

Earth Planet Sp

Geologic evidence has shown that unusual tsunami deposits are traced as high as 18 m above the current sea level or as far as 1-4 km inland from the shoreline on the Pacific coast of eastern Hokkaido, and that such unusual tsunamis have recurred at about 500 year interval with the most recent event in the 17th century. We computed coastal tsunami heights along the Hokkaido and Sanriku coasts and inundation at five coastal marshes in Hokkaido where the tsunami deposits were mapped. Three types of faults were tested: giant fault, tsunami earthquake and interplate earthquake models. The giant fault model, with the largest seismic moment, yields the lowest tsunami heights and smaller inundation than the distribution of tsunami deposits in Hokkaido, while the tsunami heights are largest in Sanriku. The tsunami earthquake model yields little inundation in Hokkaido and the smallest heights in Sanriku. The interplate earthquake model produces the largest tsunami heights and inundation in Hokkaido, reproducing the distribution of tsunami deposits on the Nemuro coast. The multi-segment interplate earthquake with variable slip (10 m on Tokachi and 5 m on Nemuro segment) can reproduce the distribution of tsunami deposits on the Tokachi coast as well, and considered as the best source model for the 17th century tsunami, although the Sanriku tsunami heights are more than 3 m, exceeding an inferred detection threshold of historical documents. The seismic moment is estimated as 8 × 10 21 N m (M w 8.5). Comparison with the recent 2003 Tokachi-oki earthquake indicates that the 17th century tsunami source was longer and located further offshore at shallower depth.