Remote sensing perspective in exploring the spatiotemporal variation characteristics and post-disaster recovery of ecological environment quality, a case study of the 2010 Ms7.1 Yushu earthquake

Figures & data

Figure 1. The study area.

Table 1. Data source in this study.

Data set	Temporal resolution	Spatial resolution	Data sources
MOD09A1 (2001 ∼ 2020)	8 Day	500 m	https: //www.nasa.gov/
MOD11A2 (2001 ∼ 2020)	8 Day	1 km	https: //www.nasa.gov/
Administrative division map of Yushu County	–	–	http://bzdt.ch.mnr.gov.cn/index.html
2010 Yushu earthquake intensity data	–	–	http://www.cea.gov.cn/
Elevation data	–	90 m	http://www.gscloud.cn/
Socioeconomic data (2010 ∼ 2019)	1 year	1 km	https://www.resdc.cn

Figure 2. Workflow of this study.

Table 2. The patterns of interaction detector.

Criterion	Interactive forms
$q(X1\cap X2)<\mathrm{\text{Min}}(q(X1),q(X2))$	Weakened, nonlinear
$\mathrm{\text{Min}}(q(X1),q(X2))<q(X1\cap X2)<\mathrm{\text{Max}}(q(X1),q(X2))$	Weakened, single factor nonlinear
$q(X1\cap X2)>\text{Max}\left(q\right(X1),q(X2\left)\right)$	Enhanced, double factors
$q(X1\cap X2)=q(X1)+q(X2)$	Independent
$q(X1\cap X2)>q(X1)+q(X2)$	Enhanced, nonlinear

Table 3. Principal component analysis results and RSEI mean from 2001 to 2020.

Year	RSEI	Indicators	PC1	PC2	PC3	PC4
2001	0.6636	NDVI	0.9058	0.4056	0.0899	0.0834
		WET	0.4065	−0.9132	0.0281	−0.0046
		NDBSI	−0.0811	0.0051	−0.9845	0.1553
		LST	−0.0880	−0.0394	0.1478	0.9843
		Eigenvalue	0.0371	0.0104	0.0042	0.0003
		Percent eigenvalue	71.25%	20.06%	8.03%	0.67%
2005	0.6621	NDVI	0.8510	0.3134	−0.3149	−0.2799
		WET	0.3716	−0.9171	0.1357	−0.0499
		NDBSI	−0.0382	0.1645	0.7904	−0.5888
		LST	−0.3691	−0.1835	−0.5076	−0.7566
		Eigenvalue	0.0256	0.0090	0.0042	0.0012
		Percent eigenvalue	63.86%	22.57%	10.50%	3.07%
2009	0.7229	NDVI	0.8956	0.4073	0.1481	−0.1002
		WET	0.4223	−0.9038	−0.0689	−0.0018
		NDBSI	−0.0980	0.1210	−0.9840	−0.0868
		LST	−0.0999	−0.0501	0.0713	−0.9912
		Eigenvalue	0.0277	0.0099	0.0031	0.0001
		Percent eigenvalue	68.02%	24.25%	7.51%	0.22%
2010	0.6032	NDVI	−0.7367	−0.0280	0.5372	−0.4097
		WET	−0.1055	−0.9779	−0.1789	0.0220
		NDBSI	0.1547	0.1325	−0.7151	−0.6686
		LST	0.6498	−0.1590	0.4098	−0.6202
		Eigenvalue	0.0353	0.0134	0.0059	0.0020
		Percent eigenvalue	62.47%	23.72%	10.36%	3.45%
2015	0.6070	NDVI	0.7026	0.4333	−0.5028	0.2565
		WET	0.6413	−0.7165	0.2742	−0.0087
		NDBSI	−0.0219	0.2490	0.6232	0.7410
		LST	−0.3076	−0.4866	−0.5326	0.6205
		Eigenvalue	0.0288	0.0163	0.0070	0.0020
		Percent eigenvalue	53.09%	30.15%	12.98%	3.79%
2020	0.7046	NDVI	0.9011	−0.2669	0.2440	−0.2394
		WET	0.3047	0.9479	−0.0925	−0.0043
		NDBSI	−0.1524	−0.1427	−0.9494	−0.2348
		LST	−0.2683	0.0990	0.1751	−0.9421
		Eigen value	0.0260	0.0097	0.0043	0.0003
		Percent eigenvalue	64.36%	24.00%	10.86%	0.78%

Figure 3. Spatial distribution of EEQ levels in Yushu County from 2001 to 2020.

Table 4. EEQ area statistics for each level from 2001 to 2020.

	Poor	Fair	Moderate	Good	Excellent
2001	264.35	1562.27	2856.75	6541.63	4199.84
	1.71%	10.13%	18.52%	42.41%	27.23%
2005	78.63	1084.30	2275.47	10699.40	1286.21
	0.51%	7.03%	14.75%	69.37%	8.34%
2009	59.87	764.87	1600.64	7708.84	5290.84
	0.39%	4.96%	10.38%	49.98%	34.30%
2010	547.46	1291.76	4076.65	8688.43	820.76
	3.55%	8.37%	26.43%	56.33%	5.32%
2015	195.29	1294.44	4287.58	9106.40	541.34
	1.27%	8.39%	27.80%	59.04%	3.51%
2020	132.73	1068.22	1665.97	7817.50	4740.64
	0.86%	6.93%	10.80%	50.68%	30.73%

Figure 4. Areas of different RSEI quality levels in Yushu County from 2001 to 2020.

Figure 5. Changes in the ecological environment in Yushu County from 2009 to 2010.

Table 5. Changes in the ecological quality of Yushu County from 2009 to 2010.

Category	Level	Area (km^2)	Total area (km^2)	Percentage (%)
Worse	Significantly worse	5317.2158	13,775.9378	89.41
	Slightly worse	8458.7220
No significant changes	No significant changes	862.3057	862.3057	5.60
Better	Slightly better	707.2644	769.0152	4.99
	Significantly better	61.7508

Table 6. Area statistics of different ecological environment change grades under different seismic intensities.

Category	Intensity
	Ⅸ	Ⅷ	VII	Ⅵ	Others
Significantly worse	116.99	368.81	1216.24	3217.52	397.66
Slightly worse	40.21	871.89	2162.62	4771.73	612.27
No significant changes	7.80	100.94	282.36	423.99	47.21
Slightly better	5.37	78.77	245.49	348.68	28.95
Significantly better	0.00	6.73	10.46	44.35	0.21

Table 7. Global moran’s I of RSEI in Yushu county from 2001 to 2020.

	2001	2005	2009	2010	2015	2020
I	0.7710	0.7462	0.7726	0.7298	0.7805	0.7598
p	0.0010	0.0010	0.0010	0.0010	0.0010	0.0010
Z	70.2158	74.1007	66.0581	64.7650	67.0536	63.6647

Figure 6. The seismic intensity of the Ms 7.1 earthquake in Yushu County, Qinghai.

Figure 7. The proportion of the ecological change grades under different seismic intensities.

Figure 8. Scatter plots of the RSEI in Yushu County from 2001 to 2020.

Figure 9. LISA of the RSEI in Yushu County from 2001 to 2020.

Table 8. The detection result of different factors of EEQ.

Year		X1	X2	X3	X4	X5
2010	q	0.350	0.044	0.004	0.041	0.029
	p	0.000	0.000	0.151	0.000	0.000
2015	q	0.376	0.034	0.003	0.061	0.027
	p	0.000	0.000	0.026	0.000	0.000
2020	q	0.457	0.034	0.004	0.055	0.099
	p	0.000	0.000	0.011	0.000	0.000

Figure 10. Results of the interaction detection. (a) 2010, (b) 2015, and (c) 2020.

Data availability statement

The data that support the findings of this study are available upon reasonable request.