Teleseismic Indication of Magmatic and Tectonic Activities at Slow- and Ultraslow-Spreading Ridges

• Published in: Journal of marine science and engineering Vol. 12; no. 4; p. 605
• Main Authors: Yan, Kaixuan, Chen, Jie, Zhang, Tao
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.04.2024
• Subjects: Cluster analysis; Earthquakes; Lithosphere; Magma; Magmatism; melt supply; mid-ocean ridge; Mid-ocean ridges; Ocean floor; Ridges; Seafloor spreading; seismic swarm; Seismicity; Seismology; slow–ultraslow-spreading ridge; Spreading; Spreading centres; Tectonic processes; Tectonics; Tectonics (Geology); teleseismicity; Temporal variations; Volcanic activity; Volcanoes; Mid-Atlantic Ridge
• ISSN: 2077-1312; 2077-1312
• DOI: 10.3390/jmse12040605

Magmatic and tectonic processes in the formation of oceanic lithosphere at slow–ultraslow-spreading mid-ocean ridges (MORs) are more complicated relative to faster-spreading ridges, as their melt flux is overall low, with highly spatial and temporal variations. Here, we use the teleseismic catalog of magnitudes over 4 between 1995 and 2020 from the International Seismological Center to investigate the characteristics of magmatic and tectonic activities at the ultraslow-spreading Southwest Indian Ridge and Arctic Gakkel Ridge and the slow-spreading North Mid-Atlantic Ridge and Carlsberg Ridge (total length of 14,300 km). Using the single-link cluster analysis technique, we identify 78 seismic swarms (≥8 events), 877 sequences (2–7 events), and 3543 single events. Seismic swarms often occur near the volcanic center of second-order segments, presumably relating to relatively robust magmatism. By comparing the patterns of seismicity between ultraslow- and slow-spreading ridges, and between melt-rich and melt-poor regions of the Southwest Indian Ridge with distinct seafloor morphologies, we demonstrate that a lower spreading rate and a lower melt supply correspond to a higher seismicity rate and a higher potential of large volcano-induced seismic swarms, probably due to a thicker and colder lithosphere with a higher degree of along-axis melt focusing there.