5:15 PM - 6:30 PM
[STT35-P03] Functional expansion of the microtremor observation cloud analysis system (BCAS)
Keywords:Underground structure model, Microtremors, Cloud analysis system
1. Introduction
In NIED has created an integrated shallow and deep underground structure model in the Kanto, Tokai, and Kumamoto regions in order to improve the prediction of wideband earthquake motion. To prepare the data necessary for that purpose, we have created a database of geological survey data such as boring data and geophysical survey data such as reflection seismic wave survey, gravity survey, and microtremor survey, and standardized the data format for each method. We have built a "Geological Information Analysis Cloud System" that enables efficient modeling. In this system, borehole data and reflection method data are provided by the national government, local governments, etc., but only microtremor exploration (array / single point) is about a series of flow from observation to analysis and modeling. It can be implemented. In this report, we have expanded the function to perform this microtremor exploration, and not only the ground survey for seismic motion prediction so far, but also the microtremor and vibration observation in the building, the ground exploration of the polar surface layer by vibration (surface wave exploration), etc. added new features.
2. Vibration observation due to fine movement and vibration in the building
In the microtremor observation cloud analysis system (BCAS), it is possible to connect the microtremor and the tablet terminal via Wi-Fi and control the setting of observation and the start / end of observation. In addition, it is possible to upload observation data to BCAS from a tablet terminal via the Internet. Regarding the analysis, the quality control of the uploaded data is performed, the analysis is performed, the result is registered in the database, and the result can be confirmed on the tablet terminal. For observations inside a building, for example, sensor are installed on the 1st and 2nd floors of a house, and the natural period of the building is measured by observing at the same time, or sensors are installed at the 4 corners of the 2nd floor. We built a system that can calculate the rigidity of the building from the shaking of the building. By installing a vibrating machine (artificial vibrating source) at an arbitrary location and vibrating, it is also equipped with a function that can automatically extract and analyze vibrations with different frequencies.
3. Ground survey by vibration (surface wave exploration)
In the previous section, it was stated that BCAS enables not only microtremor observation but also surveys that give artificial vibration. Surface wave exploration is also possible because it is possible to investigate by vibration even on the ground. Due to the Wi-Fi performance of the tablet terminal, it will be a small-scale exploration, but it will be conducted by surface wave exploration by installing a microtremor at about 10 points with a survey line length of several tens of centimeters to 20m. Basic analysis is possible. In particular, we are proceeding with verification with private businesses to improve the analysis accuracy from the ground surface to a depth of about 10 m so that it can be used for small-scale structures such as those for houses.
4. Summary
We could easily carry out various exploration and analysis using a microtremor and its quality control, and it became possible to create a database. In the future, we would like to proceed with necessary development so that we can provide systems to industry, government, and academia, and accelerate the nationwide expansion of underground structure modeling.
In NIED has created an integrated shallow and deep underground structure model in the Kanto, Tokai, and Kumamoto regions in order to improve the prediction of wideband earthquake motion. To prepare the data necessary for that purpose, we have created a database of geological survey data such as boring data and geophysical survey data such as reflection seismic wave survey, gravity survey, and microtremor survey, and standardized the data format for each method. We have built a "Geological Information Analysis Cloud System" that enables efficient modeling. In this system, borehole data and reflection method data are provided by the national government, local governments, etc., but only microtremor exploration (array / single point) is about a series of flow from observation to analysis and modeling. It can be implemented. In this report, we have expanded the function to perform this microtremor exploration, and not only the ground survey for seismic motion prediction so far, but also the microtremor and vibration observation in the building, the ground exploration of the polar surface layer by vibration (surface wave exploration), etc. added new features.
2. Vibration observation due to fine movement and vibration in the building
In the microtremor observation cloud analysis system (BCAS), it is possible to connect the microtremor and the tablet terminal via Wi-Fi and control the setting of observation and the start / end of observation. In addition, it is possible to upload observation data to BCAS from a tablet terminal via the Internet. Regarding the analysis, the quality control of the uploaded data is performed, the analysis is performed, the result is registered in the database, and the result can be confirmed on the tablet terminal. For observations inside a building, for example, sensor are installed on the 1st and 2nd floors of a house, and the natural period of the building is measured by observing at the same time, or sensors are installed at the 4 corners of the 2nd floor. We built a system that can calculate the rigidity of the building from the shaking of the building. By installing a vibrating machine (artificial vibrating source) at an arbitrary location and vibrating, it is also equipped with a function that can automatically extract and analyze vibrations with different frequencies.
3. Ground survey by vibration (surface wave exploration)
In the previous section, it was stated that BCAS enables not only microtremor observation but also surveys that give artificial vibration. Surface wave exploration is also possible because it is possible to investigate by vibration even on the ground. Due to the Wi-Fi performance of the tablet terminal, it will be a small-scale exploration, but it will be conducted by surface wave exploration by installing a microtremor at about 10 points with a survey line length of several tens of centimeters to 20m. Basic analysis is possible. In particular, we are proceeding with verification with private businesses to improve the analysis accuracy from the ground surface to a depth of about 10 m so that it can be used for small-scale structures such as those for houses.
4. Summary
We could easily carry out various exploration and analysis using a microtremor and its quality control, and it became possible to create a database. In the future, we would like to proceed with necessary development so that we can provide systems to industry, government, and academia, and accelerate the nationwide expansion of underground structure modeling.