In recent years, El Nio Modoki (a type of pseudo-El Nio) has been distinguished as a unique large-scale ocean warming phenomenon happening in the central tropical Pacific that is quite different from the traditional El Nio. In this study, EOF analysis was used to successfully separate El Nio and El Nio Modoki. The abilities of the NINO3 index, NINO3.4 index, NINO1+2 index and NINO4 index in characterizing El Nio were explored in detail. The resulting suggestion was that, comparatively, NINO3 is the op... 相似文献
Classical 3D/4D variation fusion is based on the theory that error follows Gaussian distribution. When using minimization iteration, the gradient of objective function is involved, and the solution of which requires the continuity of data. This paper adopted the extended classical 3D/4D variation fusion method, and explicitly applied the prior knowledge, which was based on L1-norm, as regularization constraint to the classical variation fusion method. Original data was firstly projected into the wavelet domain during the implementation process, and new fusion model was adopted for data fusion in wavelet space, then inverse wavelet transform was used to project the result to the observation space. Ideal experiment was carried out by using linear advection-diffusion equation as four-dimensional prediction model, which made a hypothesis of the discontinuity with the data between background and observation, and that meant the derivatives between left and right were not equal on some points. The result of the experiment showed that the method adopted here was practicable. A further research was also done for multi-source precipitation fusion. Firstly, CMORPH inversion precipitation data were corrected through PDF (Probability Density Function, PDF) matching method based on GAMMA fitting function. Then corrected data was fused with the observation one. By comparison with the reference field, the result showed that this method can keep some outliers better, which might represent certain weather phenomenon. The L1-norm regularization variation fusion in this paper provided a possible way to deal with discrete data, especially for jump point. 相似文献
The Izu-Ohshima-Kinkai earthquake (M = 7.0 on the Richter scale) occurred at 12h24 Japan Standard Time on 14 January 1978 in Sagami Bay, and caused hazards in the eastern to central Izu Peninsula. The meizoseismal zone extended 15 km from east to west by 20 km from north to south.
The aftershock zone shifted westward to the interior of the peninsula. The largest aftershock (M = 5.8) struck the central to western part of the peninsula on 15 January, causing severe damage in its mountainous terrain.
Most of the hazards related to slope failures of sea cliffs, river cliffs and road cuttings of convex vertical section with the upper parts sloping gently and the lower parts steeply.
Large slope failures occurred close to the activated faults, indicating that the shocks and displacement were locally amplified along the activated faults.
In the meizoseismal zone, high embankments of roads and housing sites on natural slopes were damaged by slides and tension cracks between the embankment and natural ground.
Subsidence and tilting of retaining structures were generally observed. Damage to high concrete retaining walls of gravity type was due to the insufficient bearing capacity of the foundation soil. Any type of retaining structure, even if seismic-resistant, would be considered ineffective in case of failure of the back slope.
Buildings in the meizoseismal zone were damaged due to sliding of the underlying embankments and ground displacement due to the activated faults.
Falling rock blocks and sliding soil masses struck cars and houses close to the foot of cliffs and steep slopes, causing many deaths and injuries.
A number of tension cracks in the middle to upper parts of steep slopes and on the shoulders of road embankments threatened to cause secondary failures, rockfalls and avalanches during heavy rain.
At a gold and silver mine, the tailings dam of a concentration plant failed due to liquefaction of the tailings.
The above experience may throw some light on the possibility of seismic failures in mountainous countries in seismically active regions of the world. 相似文献
The organic-rich shale of the Shanxi and Taiyuan Formation of the Lower Permian deposited in a marine-continental transitional environment are well developed in the Ordos Basin, NW China, which is considered to contain a large amount of shale hydrocarbon resources. This study takes the Lower Permian Shanxi and Taiyuan shale collected from well SL# in the Ordos Basin, NW China as an example to characterize the transitional shale reservoir. Based on organic geochemistry data, X-ray diffraction (XRD) analysis, field-emission scanning electron microscopy (FE-SEM) observations, the desorbed gas contents of this transitional shale were systematically studied and the shale gas potential was investigated. The results indicate that the Lower Permian Shanxi and Taiyuan shale has a relatively high total organic carbon (TOC) (average TOC of 4.9%) and contains type III kerogen with a high mature to over mature status. XRD analyses show that an important characteristic of the shale is that clay and brittle minerals of detrital origin comprise the major mineral composition of the marine-continental transitional shale samples, while the percentages of carbonate minerals, pyrite and siderite are relatively small. FE-SEM observations reveal that the mineral matrix pores are the most abundant in the Lower Permian shale samples, while organic matter (OM) pores are rarely developed. Experimental analysis suggests that the mineral compositions mainly govern the macropore development in the marine-continental transitional shale, and mineral matrix pores and microfractures are considered to provide space for gas storage and migration. In addition, the desorption experiments demonstrated that the marine-continental transitional shale in the Ordos Basin has a significantly potential for shale gas exploration, ranging from 0.53 to 2.86 m3/t with an average value of 1.25m3/t, which is in close proximity to those of terrestrial shale (1.29 m3/t) and marine shale (1.28 m3/t). In summary, these results demonstrated that the Lower Permian marine-continental transitional shale in the Ordos Basin has a significantly potential for shale gas exploration. 相似文献