I have always been interested in a variety of seismic observations related to earthquakes, volcanoes, landslides, active faults and subduction zones for more than 30 years. In the past decade, my major research works have been focusing on two active volcanoes in Taiwan (Tatun volcano group and Turtle island). Through publishing more than 20 papers, we have created a new era for active volcanoes in Taiwan. Several integrated projects have been ongoing or planed now for improving the basic research as well as volcanic prevention. A brief summary for our latest accomplishments is shown below.
1. Since 2011, we have established the Taiwan Volcano Observatory at Tatun (TVO) for reaching the major purpose of volcanic prevention as well as providing an important platform to study Taiwan volcanoes. The future eruption might be warning through the possible precursors such as significant increase of volcanic earthquakes, composition variations of volcanic gases or fluids, crustal deformation and geothermal anomalies.
2. A new method has been developed for detecting magma reservoirs through evidence of both the S-wave shadow and P-wave delay (Lin, 2016; Lin et al., 2018b). Instead of the traditional tomography for imaging magma reservoirs, we employed a simple idea of S-waves missing in the liquid for distinguishing the magma reservoirs from the solid earth. The absence of S-waves in the reservoir is also confirmed by the delay of P-wave arrivals. The results show both of the Tatun volcano group and Turtle island are active volcanoes and then the potential eruptions can’t be totally excluded in the future. In order to improve the understanding of both location and geometry of the magma reservoir, we successfully deployed Formosa Array for collecting seismic data generated by a huge number of local- and tele-earthquakes. Through the seismic tomography, both location and geometry of the magma reservoir was obtained at the depths between 8 and 20 km beneath the Tatun volcano group (Huang, Wu, Lin et al., 2021).
3. It is the first to detect heartbeat-like seismicity (Lin, 2017b) and a seismicity conduit (Pu, Lin* et al., 2020b) at the long-rest volcanoes in the world. Both observations consistently suggest a pumping system exists in the volcanic conduit. Thus, the volcanic conduit beneath the Dayoukeng fumarole might be one of the most possible magma pathways if the Tatun volcano group erupts again.
4. Detection of volcanic sounds in the Tatun volcano group (Lin, 2017a; Lin et al., 2018a) indicates the small-scale phreatic eruptions might be occasionally taken place between the major magmatic eruptions. Although the volcanic impact by phreatic eruptions might not be as strong as magmatic eruptions, the former might be more frequent than the latter. Both volcanic and phreatic eruptions can’t be excluded in the future.
5. A major hydrothermal reservoir has been revealed by the low-velocity zone at depths (0.5-2.5 km) in the Tatun volcano group (Lin et al., 2020). This result provides an important information for evaluating the geothermal exploration in the future.
6. New discovery of mantle diapirs beneath active volcanoes (Lin et al., 2021) is a provocative study to claim that magma generation in the mantle wedge is likely formed by the mélange diapirs that were mixed by the subducted sediments, alternated crust and mantle wedge rocks. Since those diapirs are just located beneath magma reservoirs around the depths between 60 and 95 km, they might be strongly associated with the magma generation in the mantle wedge. This observation provides a new concept to discuss the mechanism of magma generation and sources.