# Development and Application of a Novel Tsunami Monitoring System Based on Submerged Mooring
## 1 Introduction  
Tsunamis are gravitational water waves in the ocean, mainly caused by subduction zone thrust earthquakes, submarine landslides, volcanic eruptions, etc., which cause fractures in the seabed strata and cause fluctuations in the seawater. When a tsunami propagates in open waters, its wavelength is long and its height is small, allowing it to travel long distances across the ocean without significant energy loss. When a tsunami wave enters the continental shelf, it causes significant damage to coastal residents and facilities due to a sharp shallower water depth, shorter wavelength, and a sudden increase in wave height [1, 2, 3]. Since the 20 th century, there have been a total of seven major tsunamis worldwide; among these, the most severe tsunami was caused by the 2004 Sumatra earthquake in Indonesia, resulting in huge casualties and property damage to coastal countries [4, 5]. Countries around the world have also begun to strengthen monitoring and early warning of tsunamis, improve their early response capabilities, and reduce personnel and property damage [6]. According to research, establishing an effective tsunami monitoring system to real-time transmit tsunami wave data can enable timely and accurate predictions of the arrival time and wave height of tsunamis when they propagate to coastal areas. Its key data can effectively ensure the accuracy of tsunami warnings and reduce the disasters causedby tsunamis. Based on the characteristics of tsunamis, real-time tsunami monitoring systems typically use buoys or submerged beacon structures. Water level monitoring sensors are deployed at anchor positions near the seabed to invert real-time tide level changes. By comparing the difference between actual and predicted tide levels, tsunami waves are determined, and tsunami data are uploaded to surface communication buoys. Then, these data are transmitted to ground observation stations through satellites to monitor real-time changes in sea level elevation related to tsunamis [7]. [PERSON] studied the use of autonomous underwater robots to monitor changes in the underwater environment and provide warnings for underwater earthquakes and tsunamis, but there is the problem of real-time and reliable data transmission [8]. Researchers have also constructed earthquake monitoring networks, as described in the literature [9]. By deploying multiple tide gauges in Morocco to form an observation array and transmitting real-time data through satellites, tsunami observation and warning were achieved [10]. The National Oceanic and Atmospheric Administration (NOAA) of the United States has deployed multiple tsunami buoys in the deep ocean, known as DART (Deep Ocean Assessment and Reporting of Tsunami) systems, which can monitor tsunami waves in real time and transmit the data back to shore station data centers. Researchers can use tsunami waves to infer their source, and issue tsunami warning information in a timely manner, which have good application effects. However, networked array systems face high costs and difficulty in maintaining underwater equipment [11]. In addition to using tide level observation technology, researchers have also conducted research on tsunami monitoring systems based on fiber-optic interference technology. For example, the State Oceanic Administration of China has deployed a tsunami monitoring system equipped with fiber-optic interference water level monitoring instruments, with a measurement accuracy of \(\pm\)1 cm, which has achieved good applications. However, the detection range of this type of fiber optic is 0-110 m, which is difficult to adapt to early warning of tsunamis in deep-sea environments [12]. Therefore, although tsunami monitoring systems have achieved good application results in tsunami warning at present, most of them have high construction and operation costs, and the reliability of real-time transmission of deep-sea data is difficult to guarantee [13; 14; 15; 16; 17]. Therefore, this study designs a new tsunami monitoring system based on a submerged beacon platform.