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Distinguishing intraplate from megathrust earthquakes using lacustrine turbidites

(2019) GEOLOGY. 47(2). p.127-130
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Abstract
Subduction zone seismicity arises from megathrust, crustal, and intraslab earthquakes, and understanding the recurrence patterns of each type is crucial for hazard assessments. Lake sediments can record earthquakes from all three seismogenic sources. Here, we studied the turbidite record of Lo Encanado, an Andean lake located in central Chile. We show that Lo Encanado turbidites can be attributed to (1) subaquatic slope failure by earthquake shaking (coseismic phase), (2) floods or human impact, and (3) postseismic catchment response. All historical events with shaking intensities >VI (modified Mercalli intensity) have triggered coseismic turbidites, but only the intraplate earthquakes triggered subaerial slope failures followed by postseismic turbidites. We argue that this contrasting result is due to different spectra of seismic waves from these earthquake sources: higher-frequency accelerations from intraplate earthquakes are hardly attenuated in rocks around the lake, whereas lower-frequency accelerations from megathrust earthquakes are amplified in soft lake sediments. We tested our findings by comparing acceleration response spectra of recent and historical intraslab and megathrust earthquakes along a longitudinal profile. Results suggest that the location of Andean lakes is ideal to distinguish earthquake sources.
Keywords
HISTORIC EARTHQUAKES, LAKE-SEDIMENTS, CENTRAL CHILE, HAZARD

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MLA
Van Daele, Maarten, et al. “Distinguishing Intraplate from Megathrust Earthquakes Using Lacustrine Turbidites.” GEOLOGY, vol. 47, no. 2, 2019, pp. 127–30.
APA
Van Daele, M., Araya-Cornejo, C., Pille, T., Vanneste, K., Moernaut, J., Schmidt, S., … Cisternas, M. (2019). Distinguishing intraplate from megathrust earthquakes using lacustrine turbidites. GEOLOGY, 47(2), 127–130.
Chicago author-date
Van Daele, Maarten, Cristian Araya-Cornejo, Thomas Pille, Kris Vanneste, Jasper Moernaut, Sabine Schmidt, Philipp Kempf, Inka Meyer, and Marco Cisternas. 2019. “Distinguishing Intraplate from Megathrust Earthquakes Using Lacustrine Turbidites.” GEOLOGY 47 (2): 127–30.
Chicago author-date (all authors)
Van Daele, Maarten, Cristian Araya-Cornejo, Thomas Pille, Kris Vanneste, Jasper Moernaut, Sabine Schmidt, Philipp Kempf, Inka Meyer, and Marco Cisternas. 2019. “Distinguishing Intraplate from Megathrust Earthquakes Using Lacustrine Turbidites.” GEOLOGY 47 (2): 127–130.
Vancouver
1.
Van Daele M, Araya-Cornejo C, Pille T, Vanneste K, Moernaut J, Schmidt S, et al. Distinguishing intraplate from megathrust earthquakes using lacustrine turbidites. GEOLOGY. 2019;47(2):127–30.
IEEE
[1]
M. Van Daele et al., “Distinguishing intraplate from megathrust earthquakes using lacustrine turbidites,” GEOLOGY, vol. 47, no. 2, pp. 127–130, 2019.
@article{8622461,
  abstract     = {Subduction zone seismicity arises from megathrust, crustal, and intraslab earthquakes, and understanding the recurrence patterns of each type is crucial for hazard assessments. Lake sediments can record earthquakes from all three seismogenic sources. Here, we studied the turbidite record of Lo Encanado, an Andean lake located in central Chile. We show that Lo Encanado turbidites can be attributed to (1) subaquatic slope failure by earthquake shaking (coseismic phase), (2) floods or human impact, and (3) postseismic catchment response. All historical events with shaking intensities >VI (modified Mercalli intensity) have triggered coseismic turbidites, but only the intraplate earthquakes triggered subaerial slope failures followed by postseismic turbidites. We argue that this contrasting result is due to different spectra of seismic waves from these earthquake sources: higher-frequency accelerations from intraplate earthquakes are hardly attenuated in rocks around the lake, whereas lower-frequency accelerations from megathrust earthquakes are amplified in soft lake sediments. We tested our findings by comparing acceleration response spectra of recent and historical intraslab and megathrust earthquakes along a longitudinal profile. Results suggest that the location of Andean lakes is ideal to distinguish earthquake sources.},
  author       = {Van Daele, Maarten and Araya-Cornejo, Cristian and Pille, Thomas and Vanneste, Kris and Moernaut, Jasper and Schmidt, Sabine and Kempf, Philipp and Meyer, Inka and Cisternas, Marco},
  issn         = {0091-7613},
  journal      = {GEOLOGY},
  keywords     = {HISTORIC EARTHQUAKES,LAKE-SEDIMENTS,CENTRAL CHILE,HAZARD},
  language     = {eng},
  number       = {2},
  pages        = {127--130},
  title        = {Distinguishing intraplate from megathrust earthquakes using lacustrine turbidites},
  url          = {http://dx.doi.org/10.1130/G45662.1},
  volume       = {47},
  year         = {2019},
}

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