Crust and Uppermost Mantle Magma Plumbing System Beneath Changbaishan Intraplate Volcano, China/North Korea, Revealed by Ambient Noise Adjoint Tomography

Abstract

Studies of volcanoes are essential for understanding the internal structure of the Earth and its evolution. Holocene intraplate volcanism is widespread across northeast (NE) China, including Changbaishan volcano (CBV), Longgang volcano (LGV), and Jingpohu volcano (JPHV) as shown in Figure 1 (Liu et al., 2001). Mt. Changbaishan (also known as Mt. Paektu in Korean), straddling the border between China and North Korea, is located more than 1,000 km northwest of the Japan Trench along which the Pacific Plate is subducting beneath the Eurasian Plate (Figure 1). As the largest and most active intraplate volcanic center in NE Asia, CBV has exhibited a complex history of eruptions spanning from the Early Miocene (∼20 Ma) to the Holocene (Wei et al., 2013). Notably, a destructive eruption in 946 CE known as the "Millennium Eruption" with a global significance (e.g., Oppenheimer et al., 2017;Wei et al., 2013) shaped a massive caldera that today is partially filled with a crater lake, covering an area of nearly 20 km 2 (see the top-middle inset in Figure 1). During July 2002 and July 2005, an episode of unrest beneath CBV signified by earthquake swarms, ground inflation, and geochemical anomalies in the gas emissions has led to growing concerns over its potential eruption in the near future (Xu et al., 2012) and has drawn much public attention from nearby countries and volcanologists worldwide (Stone, 2011;Witze, 2016).

Seismicity and Magmatic System of the Changbaishan Intraplate Volcano in East Asia

“…Our 3‐D V p and V s models have higher resolution in the upper crust beneath the Tianchi volcanic area as compared with previous tomography results (Fan & Chen, 2019; Fan et al., 2022; H. Zhu et al., 2019). The identified volcanic earthquakes in Section 3.1 are also displayed in Figure 8 to get further insight into the linkage between the crustal magmatic system and volcanic seismicity.…”

“…A number of geophysical studies using 3‐D deep seismic sounding, 2‐D and 3‐D magnetotelluric sounding, 3‐D gravity modeling, and ambient noise tomography have been conducted to reveal locations and geometries of potential magma chambers beneath the CBV over the past two decades (Choi et al., 2013; Fan & Chen, 2019; Fan et al., 2022; Kim et al., 2017; Qiu et al., 2014; Tang et al., 2001; Yang et al., 2021; X. Zhang et al., 2002; H. Zhu et al., 2019). The 3‐D deep seismic sounding study revealed a low‐ V p zone at depths of 9–15 km beneath the Changbaishan‐Tianchi volcanic area, indicating the existence of a magma reservoir (X. Zhang et al., 2002).…”

“…They revealed a middle-crustal low-V s zone at depths of 8-15 km beneath the CBV, which may indicate a magma chamber. Fan et al (2022) obtained a 3-D crust-upper mantle V s model beneath the CBV by applying ambient noise adjoint tomography, which shows a prominent low-V s mush zone in the lower crust and a narrow magma conduit situated in the uppermost mantle. In addition, the existence of crustal magma chambers beneath the CBV is also supported by previous petrological and geochemical studies (Pan et al, 2017;Yi et al, 2021).…”

Pervasive Crustal Volcanic Mush in the Highly Stretched Sunda Plate Margin of Northern Sumatra

“…(2010) shows a ∼4,300 km 3 LVL in the same area with a melt fraction of ∼32%. Relatively low melt fraction estimates can be caused by the resolution limits, the wavefront healing effect, and non‐uniqueness of seismic tomography techniques (Fan et al., 2022; Paulatto et al., 2019, 2022; Rasht‐Behesht et al., 2020). For instance, the wavefront healing effect can lead to ∼50% melt fraction underestimation (Paulatto et al., 2019).…”

“…In addition, relatively low melt fractions are reported for some volcanic regions, with estimates from 2% to 10% for the intra‐crustal LVLs with several‐kilometer thicknesses, for example, in Northeast Japan (K. X. Chen et al., 2020), Changbaishan volcano (Fan et al., 2022), and Marapi volcano (Nurfiani et al., 2021) (Figure 4e). Even for the same volcano, different studies show dramatic differences in melt fraction estimates.…”