Evidence for coseismic and aseismic uplift in the last 1000 years in the focal area of a shallow thrust earthquake on the Noto Peninsula, west‐central Japan

Abstract

Raised shorelines on the Noto Peninsula on the western coast of central Japan suggest a millennial history of recurrent uplift. Emergence of the coastline by up to 50 cm was recently recorded in association with a moderate earthquake (Mw 6.7) on 25 March 2007. The shoreline uplift is indicated by the displacement of sessile organisms such as calcareous tubeworms, which can also be examined as indicators of past shifts in shoreline level. Three levels of pre‐2007 paleo‐shorelines are thus identified on this stretch of the Japan Sea coast. The lowest of these, dated at AD 1720–1950, tilts northward away from the likely source of a pair of ca. M 6.4 earthquakes in 1892, which occurred in a different area to the 2007 earthquake. The middle paleo‐shoreline, dated at AD 1430–1655, records a 30–40 cm emergence that may be aseismic. The high paleo‐shoreline, dated at AD 1025–1235, records a coseismic uplift of 50 cm and is limited to the area raised coseismically in 2007. The most recent event preceding the 2007 earthquake thus appears to have occurred approximately 1000 years ago.

Fossil tubeworms link coastal uplift of the northern Noto Peninsula to rupture of the Wajima-oki fault in AD 1729

“…The coseismic crustal deformation caused by the 2007 earthquake has been estimated based on geodetic measurements, including measurements made using a global positioning system (GPS) (Ozawa et al, 2008), synthetic aperture interferometry (InSAR) (Ozawa et al, 2008), and airborne LiDAR (Nohara et al, 2007). These findings are consistent with the estimated uplift based on the distribution of supra-, mid-, and infra-littoral organisms (Awata et al, 2008;Hiramatsu et al, 2008;Shishikura et al, 2009).…”

“…Because the difference between the global mean and the local reservoir effect (ΔR) has not been reported for this area, we calculated the calendar year assuming ΔR = 0. Shishikura et al (2009) adopted ΔR = -25 ± 28 years for a survey of the western coast of the Noto Peninsula, based on survey results for a different region in Japan. If we use this value for ΔR, the difference in the vertical displacement is estimated to be 0.06 m at most and does not alter the observations presented in this paper.…”

Submerged notches, coastal changes and tectonics in the Rijeka area, NW Croatia

“…Clearly, evidence of slow vertical motions exists for different environments Stiros et al, 1994;Natawidjaja et al, 2007;Shishikura et al, 2009). Still such motions reflect interseismic displacements, mostly transient motions between major earthquakes producing crustal deformation, and their amplitude is usually of a scale equal to that of earthquakes.…”

Tectonic and morphosedimentary features of the 2010 Chile earthquake and tsunami in the Arauco Gulf and Mataquito River (Central Chile)

“…Coseismic coastal land-level changes have been estimated by intertidal organisms in different tectonic settings (subduction zones, strike-slip fault systems, and continental thrust belts) by means of barnacles, corals, coralline algae, serpulids and molluscs (i.e. Plafker and Ward, 1992;Ortlieb et al, 1996;Ramírez-Herrera and Orozco, 2002;Ferranti et al, 2007;Shishikura et al, 2009;Castilla et al, 2010;Farías et al, 2010;Vargas et al, 2011;Melnick et al, 2012) but as has been pointed by Melnick et al (2012): "few studies have focused on the distribution of such markers along an uplifted coastline, discussing the influence of local site effects on the accuracy of uplift measurements and the specific methodological aspects that may improve the reliability".…”