Surface rupture and characteristics of a fault associated with the 2011 and 2016 earthquakes in the southern Abukuma Mountains, northeastern Japan, triggered by the Tohoku-Oki earthquake

Earth, Planets and Space

Table 2 Radiocarbon ages of the Mochiyama trench

Sample name	Sample wall	Unit	Material	Pretreatment^a	δ¹³C (‰)	¹⁴C age (yr BP)	Calibrated age (2σ)	Lab number
WC-8	West wall	110	Charcoal	AAA	− 24.91 ± 0.36	247 ± 20	1636–1670 AD (74.2%) 1780–1800 AD (21.2%)	YU-7142
WC-9	West wall	114	Charcoal	AAA	− 27.42 ± 0.40	183 ± 20	1663–1685 AD (18.3%) 1733–1808 AD (55.4%) 1928 AD (21.7%)	YU-7143
WC-10	West wall	114	Charcoal	AAA	− 25.28 ± 0.43	181 ± 20	1663–1685 AD (18.3%) 1731–1809 AD (55.4%) 1927 AD (21.7%)	YU-7018
WC-11	West wall	130	Charcoal	AAA	− 27.21 ± 0.56	3058 ± 23	1404–1260 BC (94.6%) 1240–1236 BC (0.8%)	YU-7019
WC-14	West wall	130	Wood fragment	AAA	− 30.34 ± 0.32	1415 ± 20	605–657 AD (95.4%)	YU-7144
WC-17	West wall	160	Twig	AAA	− 26.90 ± 0.37	1702 ± 20	257–296 AD (17.8%) 321–397 AD (77.6%)	YU-7145
SC-6′	South wall	160	Twig	AAA	− 29.08 ± 0.24	1592 ± 20	415–537 AD (95.4%)	YU-7146

^aAAA indicates that NaOH concentration reached 1.0 mol/L in acid–alkali-acid pretreatment