Response of tree rings to earthquakes during the past 350 years at Jiuzhaigou in the eastern Tibet

Jiawei Fan; Xiaotong Wei; Wei Shi; Qiaoqiao Guo; Siqi Zhang; Hongyan Xu; Huiming Song; Chenxi Xu; Wenling An; Hanchao Jiang

doi:10.1016/j.scitotenv.2020.138714

Response of tree rings to earthquakes during the past 350 years at Jiuzhaigou in the eastern Tibet

Sci Total Environ. 2020 Aug 20:731:138714. doi: 10.1016/j.scitotenv.2020.138714. Epub 2020 May 8.

Authors

Jiawei Fan¹, Xiaotong Wei², Wei Shi², Qiaoqiao Guo², Siqi Zhang², Hongyan Xu², Huiming Song³, Chenxi Xu⁴, Wenling An⁴, Hanchao Jiang⁵

Affiliations

¹ State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China. Electronic address: jwfan@ies.ac.cn.
² State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China.
³ Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.
⁴ Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China; CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, China.
⁵ State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China. Electronic address: hcjiang@ies.ac.cn.

PMID: 32422435
DOI: 10.1016/j.scitotenv.2020.138714

Abstract

Trees growing in the tectonically active and climatically sensitive regions, such as the Tibetan Plateau, frequently suffer damage from strong earthquakes and extreme hydro-climatic events. Spruce trees in the Jiuzhaigou National Park exhibited abrupt periods of growth suppression with durations of 3-9 years, which was demonstrated to have recorded five seismic events during the last 350 years after excluding the climatic impacts. The ring-width reductions occurred immediately after earthquakes in the growing seasons of 1748, 1879 and 2017, and one year later in 1961 when the earthquake occurred after the growing season in 1960. In contrast, seismic signals of the 1976 earthquake were moderated in the tree-ring indices by improved climatic conditions in 1975. The intensity prediction equation and isoseismal modelling results suggested that past earthquakes required a minimum intensity threshold of 6.2-6.8 MMI to significantly impact tree growth, thus indicating a minimum magnitude threshold of M_w5.3 for near-field (≤20 km) earthquakes and M_w7.4 for regional (≤115 km) earthquakes. These results would greatly improve the dendroseismological reconstruction of past earthquake characteristics and the valid assessment of future probabilities in the eastern Tibet, and help to identify and eliminate seismic signals in the dendroclimatological studies in the hazardous environments.

Keywords: Dendroclimatology; Dendroseismology; Growth suppression; Hazardous environment; Shaking intensity; Tibetan Plateau.

MeSH terms

Earthquakes*
Seasons
Tibet