大陆型山谷冰川冰震的规律和影响因素——以老虎沟12号冰川为例

陈宇乔

海洋学研究 ›› 2018, Vol. 36 ›› Issue (3) : 50-56.

PDF(1981 KB)
PDF(1981 KB)
海洋学研究 ›› 2018, Vol. 36 ›› Issue (3) : 50-56. DOI: 10.3969/j.issn.1001-909X.2018.03.005
研究论文

大陆型山谷冰川冰震的规律和影响因素——以老虎沟12号冰川为例

  • 陈宇乔1,2
作者信息 +

Rule and affecting factors of seismic events in valley glacier with continental features: A case study on Laohugou Glacier No.12

  • CHEN yu-qiao1,2
Author information +
文章历史 +

摘要

2015年10月,利用便携式宽频带地震仪在祁连山老虎沟12号冰川上进行了9 d的冰震观测,在台站的震动信号中识别出大量与冰川动态特性相关的冰震。根据信号的频率等特征,可将其分为短周期冰震和长周期冰震。短周期冰震的持续时间大多在0.1 s以下,频谱集中在20~100 Hz之间,其数量可达每天6 600个,占所检测到冰震的绝大部分。长周期冰震持续时间可达几十秒至数小时,其地震波形频率集中在0.1~10 Hz,观测期间检测到296次长周期冰震。对比冰震发震时间和当地气温发现:气温下降,短周期冰震事件数量快速增加;气温升高,短周期冰震数量逐渐减少。短周期冰震的发震时间分布呈现出以1 d为周期变化的特征。利用麦克斯韦模型模拟的冰川在气温影响下的应力变化可以解释观测到的冰震日变性:当气温下降,冰川温度下降,冰体积收缩并产生应变,相应的拉张应力使得冰裂隙破裂而产生短周期冰震信号。

Abstract

Icequakes on Laohugou Glacier No.12 were observed by operating a portable digital seismometer for 9 days in Oct. 2015. Lots of seismic signals relating to glacier dynamic characteristics were found. On the basis of signal frequency and duration time, two types of seismic event can be divided. Short-period icequakes have time duration less than 0.1 s, the frequency domains are among 20-100 Hz and the numbers are up to 6 600 per day. The majority of seismic events are short-period icequakes. Long-period icequakes have time duration from several minutes to several hours, the frequency domains are among 0.1-10 Hz and the numbers are up to 296 during the observation. Comparing the time distribution of short-period icequakes with local air temperature, it is found that once temperature drops, the numbers of short-period icequake increase rapidly. And once temperature rises, the numbers of short-period icequake decrease. The time distributions of short-period icequakes have a diurnal cycle. It is inferred that once air temperature decreases, temperature of glacier ice decreases and as a result, the fracture at the surface of glacier under tensile thermal stress was happened. Using Maxwell Model to calculate glacier stress change, the diurnal cycle of short-period icequakes can be explained.

关键词

冰川 / 冰震 / 日变周期 / 冰裂隙 / 麦克斯韦模型

Key words

glacier / icequake / Laohugou Glacier No.12 / diurnal cycle / fracture / Maxwell Model

引用本文

导出引用
陈宇乔. 大陆型山谷冰川冰震的规律和影响因素——以老虎沟12号冰川为例[J]. 海洋学研究. 2018, 36(3): 50-56 https://doi.org/10.3969/j.issn.1001-909X.2018.03.005
CHEN yu-qiao. Rule and affecting factors of seismic events in valley glacier with continental features: A case study on Laohugou Glacier No.12[J]. Journal of Marine Sciences. 2018, 36(3): 50-56 https://doi.org/10.3969/j.issn.1001-909X.2018.03.005
中图分类号: P343.6+2   

参考文献

[1] DYURGEROV M B, MEIER M F. Twentieth century climate change: Evidence from small glaciers[J]. Proceedings of the National Academy of Sciences, 2000, 97(4): 1 406-1 411.
[2] CARMICHAEL J D, PETTIT E C, HOFFMAN M, et al. Seismic multiplet response triggered by melt at Blood Falls, Taylor Glacier, Antarctica[J]. Journal of Geophysical Research: Earth Surface, 2012, 117(F3): 2 156-2 202.
[3] WANG Zong-tai, LIU Chao-hai, YOU Gen-xiang, et al. Glacier inventory of China I. Qilian mountains[M]. Lanzhou: Lanzhou Institute of Glaciaology and Cryopedology, 1981.
王宗太, 刘潮海, 尤根祥,等. 中国冰川目录(祁连山区)[M].兰州:中国科学院兰州冰川冻土研究所, 1981.
[4] SUN Wei-jun, LI Yan, QIN Xiang, et al. Characteristics of micrometeorological elements in accumulation zone of Laohugou Glacier No. 12 in Qilian Mountains[J]. Plateau Meteorology, 2013, 32(6): 1 673-1 681.
孙维君, 李艳, 秦翔,等. 祁连山老虎沟12号冰川积累区微气象特征[J]. 高原气象, 2013, 32(6):1 673-1 681.
[5] STEVENSON P R. Microearthquakes at Flathead Lake, Montana: A study using automatic earthquake processing[J]. Bulletin of the Seismological Society of America, 1976, 66(1): 61-80.
[6] WALTER F, CLINTON J F, DEICHMANN N, et al. Moment tensor inversions of icequakes on Gornergletscher, Switzerland[J]. Bulletin of the Seismological Society of America, 2009, 99(2A): 852-870.
[7] MIKESELL T D, WIJK K, HANEY M M, et al. Monitoring glacier surface seismicity in time and space using Rayleigh waves[J]. Journal of Geophysical Research: Earth Surface, 2012, 117: F2.
[8] NISHIO F. Studies on thermally induced fractures and snowquakes of polar snow cover[J]. Memoirs of National Institute of Polar Research. Ser. C, Earth Sciences, 1983, 14: 1-48.
[9] TURCOTTE D, SCHUBERT G. Geodynamics[M]. Cambridge:Cambridge University Press, 2014.
[10] LA PLACA S J, POST B. Thermal expansion of ice[J]. Acta Crystallographica, 1960, 13(6): 503-505.
[11] SCHULSON E M. The structure and mechanical behavior of ice[J]. JOM Journal of the Minerals, Metals and Materials Society, 1999, 51(2): 21-27.
[12] DEELEY R M. The viscosity of ice[J]. Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character, 1908, 81(547): 250-259.
[13] NIMMO F, MANGA M. Geodynamics of Europa's icy shell[M]. Europa:The University of Arizona Press USA, 2009: 382-404.
[14] RÖÖSLI C, WALTER F, HUSEN S, et al. Sustained seismic tremors and icequakes detected in the ablation zone of the Greenland ice sheet[J]. Journal of Glaciology, 2014, 60(221): 563-575.

基金

南北极环境综合考察与评估专项项目资助(CHINARE 03-03, 01-03, 03-04)

PDF(1981 KB)

Accesses

Citation

Detail

段落导航
相关文章

/