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Emerged Coral Reefs Record Holocene Low‐Angle Normal Fault Earthquakes
Author(s) -
Biemiller James,
Taylor Frederick,
Lavier Luc,
Yu TsaiLuen,
Wallace Laura,
Shen ChuanChou
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl089301
Subject(s) - geology , seismology , fault (geology) , slip (aerodynamics) , holocene , coral , seismic gap , episodic tremor and slip , slipping , paleontology , oceanography , tectonics , subduction , physics , thermodynamics , mechanical engineering , engineering
Low‐angle normal faults (LANFs; dip <30°) accommodate kilometers of crustal extension, yet it remains unclear whether these faults can host large earthquakes or if they predominantly creep aseismically. Most active LANFs typically slip at rates of <3 mm/year. Here, we report U‐Th ages from a series of distinct levels of formerly shallow‐living corals killed by uplift‐induced emergence of the footwall of one of the world's fastest‐slipping LANFs, the Mai'iu fault in Papua New Guinea, which slips at rates of 8–12 mm/year. Coral ages and coastal morphology indicate punctuated episodic uplift events consistent with seismic slip on the Mai'iu fault. Maximum episodic uplift increments of 0.5–1.8 m imply earthquakes of M w > 7. We present the first coral paleoseismological record of normal fault earthquakes, which constrain the timing and surface uplift patterns of multiple LANF seismic cycles and confirm that LANFs can slip in large ( M w > 7) earthquakes.