要有效地检查地震前的地壳变动,伴随板块俯冲出现的地壳变动等,必须在大范围内并加密设置观测仪器。因此,安装在地表附近(路堑、沿铁路的沟等)的仪器也需要制造出能够排除气象干扰的观测仪器。哈格特等人提出的二液体倾斜仪 To effectively check the crustal changes before the earthquake and the crustal changes that occur along with the plate subduction, observation instruments must be installed in a large area and encrypted. Therefore, instruments installed near the earth’s surface (cutting, ditches along a railway, etc.) also need to create observational instruments capable of excluding weather interference. Hagel et al. Proposed two liquid inclinometers