基于理论地震图方法的波导结构对 地下核爆炸Lg波传播特性研究

何永锋; 李锴; 刘炳灿; 姚国政; 赵克常; 张献兵; 曾乐贵

doi:10.11939/jass.2015.02.006

基于理论地震图方法的波导结构对地下核爆炸Lg波传播特性研究

1.
中国北京 100072 装甲兵工程学院
2.
中国北京 100871 北京大学地球与空间科学学院

基金项目: 国家自然科学基金(41374068)资助.

详细信息

通讯作者:
何永锋, e-mail: heyfeng@sina.com

中图分类号: P315.3⁺1
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出版历程
- 收稿日期: 2014-06-11
- 修回日期: 2014-11-21
- 发布日期: 2015-02-28

The characteristics of Lg waves induced by the underground nuclear explosions in the waveguides using frequency-wavenumber algorithm

1.
Academy of Armored Force Engineering, Beijing 100072, China
2.
School of Earth and Space Sciences, Peking University, Beijing 100871, China

摘要

摘要: 基于频率-波数域算法的理论地震波形图方法，可以数值模拟频率达到10 Hz、震中距达1000 km的区域理论地震波形图. 该算法适用于计算大量分层地壳结构中激发的导波Lg波. 本文在前苏联东哈萨克斯坦地下核试验场至我国乌鲁木齐台站间的地球介质速度模型中，引入速度梯度结构、速度扰动分布的薄叠加层结构、降低Q值结构以及速度扰动与Q值变化的综合结构来模拟实际地壳波导结构，较好地模拟出东哈萨克斯坦地下核爆炸地震在乌鲁木齐台站记录的宽频带地震波形图，模拟出完整的Lg波序列，该序列符合Lg波能量分布特征，且能够解释Lg波波尾的特征. 结果表明， Lg波的形状和峰值结构均依赖于地壳的不同波导结构.
- 频率-波数域算法 /
- 地下核爆炸 /
- Lg波
Abstract: Based on the frequency-wavenumber algorithm，we can simulate high frequency (10 Hz) regional seismograms (up to a distance of more than 1000 km). The algorithm is used to synthesize the regional waveguides on Lg waves in a medium consisting of a large number of crustal layers. Based on the crustal velocity model from a former Soviet nuclear test site located in eastern Kazakhstan to WMQ station in China, this paper build up a modified model consisting of thin layers with an alternating high and low-velocity, a velocity gradient near the surface， the lower Q values， and the composite structure of velocity perturbation and different Q values so as to match the real crustal structure. And then we simulate very well the regional seismograms in WMQ station by underground nuclear explosions of the test site in eastern Kazakhstan. The synthetic results conform to the energy distribution characteristics of Lg waves, and explain the feature of the coda. The numerical results suggest that the shapes and peak amplitudes of Lg waves all depend on the different crustal waveguides.
- frequency-wavenumber algorithm /
- underground nuclear explosion /
- Lg wave

HTML全文

图 1 前苏联东哈萨克斯坦地区地下核试验在乌鲁木齐台站记录的地震波形图

Figure 1. Seismograms of underground nuclear explosions at a former Soviet test site located at eastern Kazakhstan recorded by the WMQ station

下载: 全尺寸图片幻灯片

图 2 (a)Steven模型；(b)速度梯度分布模型；(c)速度扰动分布模型

Figure 2. (a)Steven model；(b)Velocity gradient model；(c)Velocity perturbation model

下载: 全尺寸图片幻灯片

图 3 基于模型1(a)和模型2(b)介质速度模型的理论地震波形图

Figure 3. Theoretical seismograms based on the velocity of Steven model(a) and velocity gradient model(b)

下载: 全尺寸图片幻灯片

图 4 基于模型1(a)和模型3(b)介质速度模型的理论地震波形图

Figure 4. Theoretical seismograms based on the velocity of Steven model(a) and velocity perturbation model(b)

下载: 全尺寸图片幻灯片

图 5 基于模型1(a)和修正Q_S(b)的介质速度模型的理论地震波形图

Figure 5. Theoretical seismograms based on the Steven model(a) and revised Steven model with modified Q_S value(b)

下载: 全尺寸图片幻灯片

图 6 基于模型3的Q值修正介质速度模型的理论地震波形图

Figure 6. Theoretical seismograms based on the perturbation model with modified Q value

下载: 全尺寸图片幻灯片

表 1 东哈萨克斯坦地区地下核试验场区速度模型

Table 1 Seismic velocity model of underground nuclear test site at eastern Kazakhstan region

层号	界面深度/km	密度/(g·cm^-3)	S波速度/(km·s^-1)	P波速度/(km·s^-1)	Q_S	Q_S-修正	Q_P
1	0	2.700	2.790	5.020	100	80	2000
2	2.000	2.700	3.000	5.400	150	120	2000
3	3.000	2.700	3.300	5.900	200	160	2000
4	5.488	2.700	3.400	6.100	600	480	2000
5	16.464	2.702	3.541	6.308	525	420	2000
6	21.952	2.807	3.703	6.597	500	400	2000
7	27.440	2.858	3.781	6.736	450	360	2000
8	32.928	2.875	3.807	6.782	400	400	2000
9	38.492	2.879	3.814	6.795	350	350	2000
10	44.996	3.372	4.573	8.147	179	179	2000
11	53.002	3.369	4.568	8.138	167	167	2000
12	62.361	3.358	4.550	8.106	159	159	2000
13	73.301	3.343	4.527	8.065	153	153	2000
14	86.081	3.336	4.517	8.047	150	150	2000
15	101.031	3.345	4.530	8.070	148	148	2000
16	118.501	3.361	4.556	8.117	148	148	2000
17	138.921	3.375	4.577	8.154	147	147	2000
18	162.801	3.378	4.581	8.161	147	147	2000
19	190.711	3.372	4.572	8.145	146	146	2000
20	223.341	3.363	4.558	8.120	146	146	2000
21	300.000	3.356	4.547	8.101	145	145	2000

下载: 导出CSV

参考文献(33)

McLaughlin K L, Barker T G, Day S M, Shkoller B, Stevens J L. 1988. Effects of Depth of Burial on Explosion and Earthquake Regional Seismograms: Regional Discrimination and Yield Estimation[R]. S-CUBED report No. SSS-R-88-9844, Jolla, California.

Patton H J. 1991. Seismic moment estimation and the scaling of the long-period explosion source spectrum[G]//AGU Geophysical Monograph 65: Explosion Source Phenomenology: 239-252.

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