High‐resolution chronology of sediment below CCD based on Holocene paleomagnetic secular variations in the Tohoku‐oki earthquake rupture zone

Abstract

Using high‐resolution paleomagnetic data, we examined the potential for obtaining precise ages from sediment core samples recovered from deep‐sea basins close to rupture zones of the 2011 and earlier earthquakes off Tohoku, Japan. Obtaining detailed stratigraphic ages from deep‐sea sediments below the calcium compensation depth (CCD) is difficult, but we found that the samples contain excellent paleomagnetic secular variation records to constrain age models. Variations in paleomagnetic directions obtained from the sediments reveal systematic changes in the cores. A stacked paleomagnetic profile closely matches the Lake Biwa data sets in southwest Japan for the past 7000 years, one can establish age models based on secular variations of the geomagnetic field on sediments recovered uniquely below the CCD. Comparison of paleomagnetic directions near a tephra and a paleomagnetic direction of contemporaneous pyroclastic flow deposits acquired by different magnetization processes shows precise depositional ages reflecting the magnetization delay of the marine sediment record.

Event Stratigraphy in a Hadal Oceanic Trench: The Japan Trench as Sedimentary Archive Recording Recurrent Giant Subduction Zone Earthquakes and Their Role in Organic Carbon Export to the Deep Sea

“…In the hadal Japan Trench, the AD 2011 Tohoku-oki earthquake remobilized young fine-grained surficial slope sediments enriched in organic matter, which was eventually deposited in the more than 7 km deep trench (Arai et al, 2013;Oguri et al, 2013;Strasser et al, 2013;Ikehara et al, 2016;McHugh et al, 2016;Kanamatsu et al, 2017;Bao et al, 2018;Kioka et al, 2019;Molenaar et al, 2019). Remarkably, the 2011 earthquake delivered >1 Tg (10 12 g) of OC to the Japan Trench between 36.0 • and 39.5 • N through the resedimentation of spatially widespread remobilization of surficial sediment with a total volume of ∼0.2 km 3 (Kioka et al, 2019).…”

Supercycle in great earthquake recurrence along the Japan Trench over the last 4000 years

“…Correlations between PSV records of NT3-19 (PC08 and PC10) and those of Lake Biwa (Ali et al 1999). The letters "A"-"G" (relative declination) and "a"-"n" (inclination) added to the PSV records are PSV labels for prominent features of age control (Ali et al 1999;Kanamatsu et al 2017). Table S1.…”

“…Therefore, we used a PSV method that has not been previously used for dating the deep-sea turbidites. The measurement procedure and the PSV records and magnetic susceptibility results are based on Kanamatsu et al (2017). Obvious peak and trough intervals on the graphs of paleomagnetic inclinations and declinations (PSV labels; "A"-"E" and "a"-"i" in Fig.…”

Paleomagnetic Secular Variation and Relative Paleointensity During the Holocene in South China—Huguangyan Maar Lake Revisited

“…A distribution of paleomagnetic secular variation (PSV) curves as even as possible across the globe during the Holocene is crucial for understanding the dynamics of the Earth's magnetic field over decadal to millennial timescales (Korte & Constable, 2005). Moreover, such curves contribute to high-resolution Holocene stratigraphy and are promising dating tools in archeology Ben-Yosef et al, 2008;Kanamatsu et al, 2017;Lougheed et al, 2014;Lund et al, 2016). During the past decades, Holocene PSV has been extensively studied, which resulted in a substantial number of reliable curves from around the globe, contributing to the establishment and progressive improvements of global geomagnetic field models, such as ARCH3k.1 (Korte et al, 2009), SED3k.1 (Korte et al, 2009), CALS3k.4 , CALS10k.1b , and pfm9k.1a ).…”