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Santorini volcano has a history of caldera‐forming eruptions, most recently in the Late Bronze Age, at 3.4 kya, and remains volcanically active. The Kolumbo submarine volcano, located 7 km to the northeast of Santorini, erupted in 1650 AD in a deadly phreatomagmatic eruption. Ongoing seismic activity and active hydrothermal venting at Kolumbo indicate this volcano is a significant hazard to the Santorini region. The magma source for Santorini and the Kolumbo edifice are considered separate in the shallow crust, though their deeper magma distribution is not yet constrained. In this study, we improve constraints on the mid‐crustal magma system of Santorini caldera and the nearby Kolumbo volcano using local earthquake tomography. We use 1515 P‐wave and 1435 S‐wave arrival times from 63 local earthquakes with magnitudes from 0.5 to 3.0 that occurred between 5 and 15 km depth together with an existing data set of active source Pg arrivals. The upper crustal magma system beneath Santorini is imaged to at least 6 km depth, and to 12 km depth beneath Kolumbo. We recover a high P‐wave velocity layer (∼6–8 km) under the Kolumbo magma reservoir that we infer is a rheologically strong seismogenic layer. We also recover a mid‐crustal magma body below 8 km depth located to the NE of Santorini and Kolumbo.
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Deep long-period earthquakes generated by second boiling beneath Mauna Kea volcano
Deep long-period earthquakes (DLPs) are an enigmatic type of volcanic seismicity that sometimes precedes eruptions but mostly occurs at quiescent volcanoes. These earthquakes are depleted in high-frequency content and typically occur near the base of the crust. We observed a near-periodic, long-lived sequence of more than one million DLPs in the past 19 years beneath the dormant postshield Mauna Kea volcano in Hawaiʻi. We argue that this DLP sequence was caused by repeated pressurization of volatiles exsolved through crystallization of cooling magma stalled beneath the crust. This “second boiling” of magma is a well-known process but has not previously been linked to DLP activity. Our observations suggest that, rather than portending eruptions, global DLP activity may more commonly be indicative of stagnant, cooling magma.
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- Award ID(s):
- 1848302
- PAR ID:
- 10183747
- Date Published:
- Journal Name:
- Science
- Volume:
- 368
- Issue:
- 6492
- ISSN:
- 0036-8075
- Page Range / eLocation ID:
- 775 to 779
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1126/science.aba4798
