汶川<i>M</i><sub>S</sub>8.0地震前后龙门山及其 邻区构造应力场时空分布特征

虎雄林; 王强; 解朝娣

doi:10.11939/jass.2015.05.004

汶川M_S8.0地震前后龙门山及其邻区构造应力场时空分布特征

1.
中国昆明 650224 云南省地震局
2.
中国昆明 650091 云南大学地球物理系

基金项目:

国家自然科学基金 41004021

国家自然科学基金 41090292

国家自然科学基金 41104036

详细信息

通讯作者:
虎雄林, e-mail: 86084639@qq.com

中图分类号: P315.72⁺7
计量
- 文章访问数: 512
- HTML全文浏览量: 241
- PDF下载量: 25
出版历程
- 收稿日期: 2015-01-16
- 修回日期: 2015-05-26
- 发布日期: 2015-08-31

Spatio-temporal distribution of tectonic stress field in Longmenshan and its adjacent regions before and after Wenchuan M_S8.0 earthquake

1.
Earthquake Administration of Yunnan Province， Kunming 650224， China
2.
Department of Geophysics， Yunnan University， Kunming 650091， China

摘要

摘要: 基于2000年7月—2009年6 月龙门山及其邻区的震源机制解资料，采用Gephart & Forsyth方法，反演得到了汶川地震前后该地区构造应力主方向的空间分布. 结果显示：沿鲜水河断裂带及其北部地区，构造应力场变化显著，区域构造应力的最大主应力方位由NNW变为NW，断层错动类型由正断型兼走滑型变为走滑型；沿龙门山断裂带的构造应力最大主应力方向仍然为近EW和NE向，但其EW向范围在向NE方向扩张，其南部汶川地震震中附近异常带范围在收缩. 另一方面，对上述时间段龙门山及其邻区不同时段构造应力场的反演结果表明，其构造应力场的特征参数(包括R值、应力洛德参数μ′以及3个主应力的方位角和仰角等)均从第13时窗开始出现显著变化，这表明第13时窗(2006年12月—2007年1月)是一个构造应力显著变化的特征窗口. 在该时窗内，地震能量积累达到一个临界状态，是汶川M_S8.0地震发生的时间节点.
- 汶川地震 /
- 龙门山 /
- 构造应力场
Abstract: Based on the focal mechanism solutions for Longmenshan and its adjacent regions from July 2000 to June 2009, the spatial distribution of the main direction of tectonic stress fields are retrieved in the regions before and after the Wenchuan M_S8.0 earthquake by using the Gephart & Forsyth method. The results show that the tectonic stress fields change significantly along Xianshuihe fault zone and the region to the north, and that the maximum principal stress direction of the regional tectonic stress shifts from NNW to NW, while the faulting changes from combined normal fault and strike-slip to strike-slip only. Significant changes can also be observed in the tectonic stress field along the Longmenshan fault zone. Although the maximum principal stress direction still approximates to the east-west and north-east, its scope is expanding towards the east-north, and the abnormal belt near the epicenter of Wenchuan earthquake shrinks. On the other hand, the retrieval results of the tectonic stress fields in Longmenshan and its adjacent regions during different periods from July 2000 to June 2009 show that the characteristic parameters of tectonic stress fields, including the R value, Lode parameter μ′, azimuths and elevation angles of three principal stresses, begin to change significantly since the thirteenth window, suggesting that the thirteenth window (December 2006 to January 2007) is a characteristic window with significant changes in the tectonic stress. In the thirteenth window, the seismic energy is accumulated to a critical state, signaling the time node for the occurrence of Wenchuan M_S8.0 earthquake.
- Wenchuan earthquake /
- Longmenshan /
- tectonic stress field

HTML全文

图 1 基于震源机制解资料获取的2000年7月-2009年6月龙门山及其邻区地震震中分布图

Figure 1. Distribution of epicenters obtained based on source mechanism solution data in Longmenshan and its adjacent regions from July 2000 to June 2009

下载: 全尺寸图片幻灯片

图 2 断层和主应力方向的两套笛卡尔坐标系投影图

x₁-x₂-x₃为断层坐标系,x′₁-x′₂-x′₃为主应力坐标系;cos^-1β_{31是两套坐标系转换的方向余弦}

Figure 2. Two sets of Descartes coordinates projection chart for fault and principal stress directions

x₁-x₂-x₃ is fault coordinate system,x′₁-x′₂-x′₃ is principal stress coordinate system,cos^-1β₃₁ is the direction cosine of the two systems

下载: 全尺寸图片幻灯片

图 3 汶川M_S8.0地震前龙门山及其邻区构造应力σ₁主方向(a)及其方差(b)分布

Figure 3. Distribution of the principal direction of tectonic stress (a) and variance (b) in Longmenshan and its adjacent regions before Wenchuan M_S8.0 earthquake

下载: 全尺寸图片幻灯片

图 4 汶川M_S8.0地震后龙门山及其邻区构造应力σ₁主方向(a)及其方差(b)分布

Figure 4. Distribution of the principal direction of tectonic stress (a) and variance (b) in Longmenshan and its adjacent regions after the Wenchuan M_S8.0 earthquake

下载: 全尺寸图片幻灯片

图 5 龙门山及其邻区不同时窗的构造应力场综合解(a)2001-06-2002-06;(b)2001-12-2002-12

Figure 5. Comprehensive solutions of tectonic stress field in Longmenshan and its adjacent regions in the periods from June 2001 to June 2002(a) and from December 2001 to December 2002

下载: 全尺寸图片幻灯片

图 6 R值随时间窗的变化趋势

Figure 6. Variation of R value with time window

下载: 全尺寸图片幻灯片

图 7 洛德应力参数μ随时窗变化趋势

Figure 7. Variation of Lode stress parameter μ with time window

下载: 全尺寸图片幻灯片

图 8 主应力方位角(a)和仰角(b)随时窗的变化趋势

Figure 8. Variation of azimuth (a) and elevation (b) of three principle stresses with time window

下载: 全尺寸图片幻灯片

图 9 地震滑动累计速度、滑动累计频度标准差及滑动释放能量相对值随时窗的变化趋势

Figure 9. Variation of the sliding accumulative rate,the standard deviation and the accumulative energy of sliding with time window

下载: 全尺寸图片幻灯片

表 1 本文反演所用的2000年7月—2002年12月部分震源机制解资料

Table 1 Partial source mechanism solution data from July 2000 to December 2002 used for inversion in this study

序号	发震时间		发震地点		震源深度 /km	M_S	节面Ⅰ			节面Ⅱ			P轴		T轴		N轴
序号	年-月-日	时:分	北纬/°	东经/°	震源深度 /km	M_S	滑动角 /°	倾角 /°	走向 /°	滑动角 /°	倾角 /°	走向 /°	方位 /°	倾角 /°	方位 /°	倾角 /°	方位 /°	倾角 /°
1	2000-07-17	19:15	29.42	104.84	7	3.8	-48	83	290	-170	43	193	232	64	344	53	116	48
2	2000-09-21	16:32	32.95	104.62	1	3.6	-59	59	292	-130	43	161	224	82	330	28	130	64
3	2000-09-23	15:00	31.23	100.70	5	4.3	92	42	129	88	48	312	66	3	220	87	311	89
4	2001-01-06	10:28	29.48	105.87	8	3.5	41	46	306	128	62	67	106	35	3	81	268	57
5	2001-02-14	15:28	29.40	101.08	8	5.1	153	44	352	50	72	242	14	43	123	73	227	52
6	2001-02-23	08:02	29.42	101.10	6	6.0	161	44	347	47	77	243	13	48	122	70	231	49
7	2001-02-23	10:12	29.43	101.03	5	4.2	0	64	340	-154	90	250	118	72	22	72	250	26
8	2001-03-01	13:19	29.47	101.05	5	3.5	9	63	325	153	82	59	105	66	10	78	254	27
9	2001-03-07	19:52	27.75	102.75	6	4.2	14	79	313	169	76	46	89	72	180	88	277	18
10	2001-03-11	22:32	29.40	101.05	5	3.5	-6	59	339	-149	85	246	117	72	18	65	238	32
11	2001-04-19	12:56	31.67	102.28	5	3.8	3	61	352	151	88	84	132	68	34	72	268	30
12	2001-04-20	04:20	32.50	102.03	5	3.6	-2	67	340	-157	88	249	117	75	22	73	245	23
13	2001-04-24	19:15	28.50	102.13	5	3.5	178	23	124	66	89	32	144	49	281	50	31	67
14	2001-04-27	14:40	31.33	100.93	5	3.9	13	81	321	171	77	53	97	75	188	87	288	15
15	2001-06-23	10:49	29.45	105.48	11	4.9	-33	39	21	-124	70	264	149	72	35	38	251	58
16	2001-08-06	02:12	30.43	103.28	5	4.2	-68	72	103	-139	28	336	30	66	164	33	290	69
17	2001-08-31	23:17	29.88	102.77	4	3.6	70	27	346	100	64	144	214	21	61	71	328	81
18	2001-09-05	10:58	30.47	101.62	5	3.5	171	58	62	33	83	327	100	62	199	73	316	34
19	2001-09-23	06:35	31.93	102.03	2	3.9	-119	27	155	-76	67	304	224	70	10	24	129	77
20	2001-09-28	06:32	28.37	104.72	11	4.3	179	50	315	40	89	225	352	62	97	63	224	40
21	2001-11-15	23:00	29.43	101.03	5	4.0	-62	37	11	-109	58	225	121	79	359	20	215	74
22	2001-12-06	03:05	29.15	104.82	14	3.8	73	19	209	95	72	12	93	28	286	63	193	85
23	2001-12-23	06:42	29.13	104.60	2	4.1	-43	14	226	-101	80	94	355	55	197	37	92	80
24	2002-01-26	09:14	31.42	103.07	5	3.8	-145	90	215	0	55	305	85	66	344	66	214	35
25	2002-02-09	17:36	28.07	104.93	5	3.6	-133	16	2	-79	79	138	57	57	215	35	321	79
26	2002-03-03	08:23	28.68	102.23	5	4.4	-86	35	20	-93	55	205	113	80	306	10	203	88
27	2002-03-03	07:06	32.37	100.97	5	3.6	42	90	115	180	48	205	241	62	348	62	115	42
28	2002-04-10	14:30	27.52	102.45	4	4.6	-64	81	210	-161	27	103	141	59	273	43	34	65
29	2002-04-29	20:54	28.42	104.70	2	3.8	-145	51	196	-45	63	310	251	83	349	40	155	51
30	2002-04-30	12:56	29.42	105.53	6	3.8	-2	49	64	-139	89	333	206	64	100	61	331	41
31	2002-05-23	22:26	27.47	102.75	5	4.0	133	89	183	1	43	92	239	58	127	60	4	47
32	2002-05-23	11:51	30.67	102.70	7	3.9	-99	24	193	-86	67	3	276	68	86	22	185	86
33	2002-05-31	11:53	30.30	104.18	5	4.4	101	21	206	86	70	40	130	25	302	66	33	87
34	2002-06-01	14:18	29.42	100.98	5	3.6	165	51	340	40	78	240	12	54	116	72	227	42
35	2002-06-21	15:05	27.65	102.73	6	3.6	140	83	186	10	50	90	236	57	131	69	15	41
36	2002-07-10	07:17	31.55	99.18	5	4.2	-98	35	316	-84	55	127	41	80	196	11	310	85
37	2002-07-17	01:15	31.62	104.02	12	3.7	-102	33	13	-82	57	179	95	78	245	13	3	84
38	2002-08-04	20:29	31.68	103.18	5	3.5	142	71	99	24	55	355	143	50	44	80	302	42
39	2002-08-05	02:16	31.54	102.43	5	3.8	48	88	110	177	42	202	234	56	347	60	108	48
40	2002-08-08	19:43	30.87	100.02	5	5.3	-162	54	312	-38	76	53	358	76	99	53	250	40
41	2002-08-17	03:54	27.84	100.82	5	4.5	6	46	141	136	85	235	288	57	179	64	60	45
42	2002-09-11	00:34	32.93	104.83	3	3.9	-160	81	303	-10	70	36	171	83	78	69	279	22
43	2002-09-12	14:31	29.50	105.68	5	3.5	-87	25	34	-91	64	218	126	70	310	20	216	89
44	2002-09-13	13:37	30.12	102.13	5	3.6	-160	42	121	-49	77	226	165	69	277	47	57	51
45	2002-09-17	04:47	32.63	102.67	5	3.8	90	38	160	90	52	340	71	7	250	83	340	90
46	2002-11-20	21:46	33.92	102.82	5	4.0	-169	79	218	-11	80	310	264	90	354	75	173	15
47	2002-11-25	14:12	30.83	99.90	5	4.7	-7	42	187	-132	86	92	330	62	218	55	89	48
48	2002-11-27	01:55	30.97	103.37	5	3.9	-105	24	112	-83	66	276	191	69	353	22	99	84
49	2002-12-12	09:10	33.10	103.93	5	4.1	175	38	252	52	87	158	281	53	37	59	155	52

下载: 导出CSV

表 2 2000年7月—2009年6月龙门山及其邻区不同时窗构造应力场的综合解

Table 2 Comprehensive solutions of the tectonic stress field in Longmenshan and its adjacent regions in different time windows from July 2000 to June 2009

时窗序号	时窗范围	窗内地震数目	综合断层类别	R值	μ	仰角/°			方位角/°
时窗序号	时窗范围	窗内地震数目	综合断层类别	R值	μ	σ₁	σ₂	σ₃	σ₁	σ₂	σ₃
1	2000-07—2001-12	23	未知	0.40	0.20	40	49	4	268	80	174
2	2001-06—2002-06	21	走滑	0.60	-0.20	32	53	17	43	189	302
3	2001-12—2002-12	28	正断	0.30	0.40	65	6	25	135	32	299
4	2002-06—2003-06	24	正断	0.20	0.60	55	25	23	151	282	24
5	2002-12—2003-12	26	逆冲	0.10	0.80	0	3	87	117	27	215
6	2003-06—2004-06	30	走滑	0.60	-0.20	29	61	1	18	196	288
7	2003-12—2004-12	31	未知	0.20	0.60	49	32	22	281	144	39
8	2004-06—2005-06	31	正断	0.80	-0.60	77	8	10	327	97	188
9	2004-12—2005-12	35	未知	0.40	0.20	40	45	18	116	262	10
10	2005-06—2006-06	42	未知	0.80	-0.60	27	44	35	136	254	26
11	2005-12—2006-12	49	逆冲	0.10	0.80	3	1	87	297	27	131
12	2006-06—2007-06	46	逆冲	0.20	0.60	2	5	84	103	13	219
13	2006-12—2007-12	70	走滑	0.10	0.80	31	59	1	270	92	0
14	2007-06—2008-06	154	逆冲	0.90	-0.80	6	6	81	2	271	138
15	2007-12—2008-12	154	逆冲	0.90	-0.80	2	4	85	2	272	118
16	2008-06—2009-06	137	逆冲	0.90	-0.80	2	4	85	2	272	118