In Northeast Japan and Izu-Bonin, arc volcanoes form in clusters or as cross-arc chains. Their occurrence emphasizes the non-uniform distributions of sub-arc temperature and fluids that control the spacing of arc volcanoes. Here, using 3-D numerical models, we show that the cessation of back-arc spreading promotes volcano clustering by triggering the formation of nascent lithospheric drips – downward protrusions of cold and dense lithosphere-adjacent to the thinned back-arc lithosphere. The nascent drips interfere with the flow of the hot asthenospheric mantle from the back-arc toward the arc, leading to gradual development of alternating hot and cold regions beneath the arc. The results indicate that along-arc variation in the sub-arc mantle temperature is largest not during back-arc spreading but after its cessation, explaining the time offset by several million years between back-arc spreading and volcano clustering in Northeast Japan and Izu-Bonin.
|Journal||Geophysical Research Letters|
|Publication status||Published - 2021 May|
Bibliographical noteFunding Information:
We thank two anonymous reviewers for useful comments, which helped to improve the manuscript. C.L. acknowledges the financial support from the National Research Foundation of Korea (Grant #: 2017R1A6A1A07015374 and 2019R1A2C1002517) and the Yonsei University (2019‐22‐0010). I.W. acknowledges the financial support from the University of Minnesota in the form of start‐up funds.
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All Science Journal Classification (ASJC) codes
- Earth and Planetary Sciences(all)