Global rupture parameters for deep and intermediate‐depth earthquakes

Poli, Piero; Prieto, G. A.

doi:10.1002/2016jb013521

Cited by 43 publications

(66 citation statements)

References 53 publications

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“…To quantify the amount of radiation given the size of an earthquake, seismologists measure the scaled energy E S = E R / M 0 . Globally, the scaled energy of shallow earthquakes is found to be scale invariant (Convers & Newman, ; Baltay et al, ; Denolle & Shearer, ), suggesting a common radiation style to all earthquakes, though such invariance may not hold for intermediate‐depth and deep focus earthquakes (Poli & Prieto, ). Additional metrics may quantify energy relative to a reference moment rate function and duration, such as that proposed by both Kanamori and Rivera () and Madariaga ().…”

Section: Introductionmentioning

confidence: 99%

Energetic Onset of Earthquakes

Denolle

2019

Geophysical Research Letters

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Earthquake radiation is broadband, and its temporal evolution carries the seismic signature of the rupture process. I use established and develop new observational metrics to quantify the temporal variation in radiated energy (seismic power) and in a time‐dependent scaled radiated energy. Universal functional forms of moment rate, seismic power, and scaled energy arise from a global database of source time functions. Earthquakes radiate mostly and most efficiently in the early stage of development of the rupture that is in the first 10–30% of the overall rupture duration. This result is independent of earthquake magnitude, depth, and focal mechanism. Beyond depth dependence in elastic properties with depth that explain variations in source duration and radiated energy, subtle differences in functional forms exist between shallow and deep earthquakes. Deep events have a slower development than shallow earthquakes, but they carry a higher peak in seismic power.

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Section: Introductionmentioning

confidence: 99%

Energetic Onset of Earthquakes

Denolle

2019

Geophysical Research Letters

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“…A few mechanisms have been proposed to explain deep earthquakes, including dehydration embrittlement (Raleigh & Paterson, ; Silver et al, ), transformational faulting of metastable olivine (Green II & Burnley, ; Green & Zhou, ; Kirby, ; Kirby et al, ; Wiens et al, ), and thermal shear instability (Hobbs & Ord, ; Kanamori et al, ; Ogawa, ; Wiens & Snider, ). The key to distinguish these mechanisms lies in high‐resolution seismological observations (Y. Chen et al, ; Houston et al, ; Persh & Houston, ; Poli & Prieto, ; Tibi, Bock, & Wiens, ; Warren & Silver, ; Ye et al, ; Zhan et al, ). For instance, finite source models of deep earthquakes in Tonga and South American subduction zones have demonstrated two types of distinct rupture characteristics at cold and warm slabs (e.g., Goes & Ritsema, ; Kikuchi & Kanamori, ; McGuire et al, ; Poli & Prieto, ; Tibi, Bock, & Wiens, ; Wiens & McGuire, ).…”

Section: Introductionmentioning

confidence: 99%

“…The key to distinguish these mechanisms lies in high-resolution seismological observations (Y. Chen et al, 2014;Houston et al, 1998;Persh & Houston, 2004;Poli & Prieto, 2016;Tibi, Bock, & Wiens, 2003;Warren & Silver, 2006;Ye et al, 2013;Zhan et al, 2014). For instance, finite source models of deep earthquakes in Tonga and South American subduction zones have demonstrated two types of distinct rupture characteristics at cold and warm slabs (e.g., Goes & Ritsema, (Ekström et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Complex and Diverse Rupture Processes of the 2018 Mw 8.2 and Mw 7.9 Tonga‐Fiji Deep Earthquakes

Fan

Wei

Tian

et al. 2019

Geophysical Research Letters

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Deep earthquakes exhibit strong variabilities in their rupture and aftershock characteristics, yet their physical failure mechanisms remain elusive. The 2018 Mw 8.2 and Mw 7.9 Tonga‐Fiji deep earthquakes, the two largest ever recorded in this subduction zone, occurred within days of each other. We investigate these events by performing waveform analysis, teleseismic P wave backprojection, and aftershock relocation. Our results show that the Mw 8.2 earthquake ruptured fast (4.1 km/s) and excited frequency‐dependent seismic radiation, whereas the Mw 7.9 earthquake ruptured slowly (2.5 km/s). Both events lasted ∼35 s. The Mw 8.2 earthquake initiated in the highly seismogenic, cold core of the slab and likely ruptured into the surrounding warmer materials, whereas the Mw 7.9 earthquake likely ruptured through a dissipative process in a previously aseismic region. The contrasts in earthquake kinematics and aftershock productivity argue for a combination of at least two primary mechanisms enabling rupture in the region.

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“…Previous studies of intermediate‐depth earthquake source parameters can be divided into those that examine events at regional distances and those that examine events globally. Examples of the latter include Poli and Prieto () and Poli and Prieto (), who also include deep earthquakes in their study. They find that intermediate‐depth earthquakes as a whole do not appear to be scale invariant, varying as

normalΔ σ \sim M_{0}^{0.19 \pm 0.02}

, and find regional differences in the source parameters that do not obviously correlate with slab properties such as the thermal parameter or plate age.…”

Section: Introductionmentioning

confidence: 99%

Source Parameter Variability of Intermediate‐Depth Earthquakes in Japanese Subduction Zones

2019

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The physical mechanism of intermediate‐depth earthquakes is still uncertain. Dehydration embrittlement and thermal shear heating mechanisms are the leading hypotheses, and each has been supported both by observations and experiments. Slab character is likely to affect either mechanism. We apply uniform processing to data sets from the two main subduction zones in Japan: the older, colder, and faster‐subducting Pacific plate and the younger, warmer, and slower‐subducting Philippine Sea plate. We compare the stress drops and radiated efficiencies of intermediate‐depth earthquakes in these settings and find no significant differences between the scaling of source properties. In particular, we find both an increase of stress drop and apparent stress with increasing moment for the Pacific Plate subduction in Hokkaido and for the Philippine Sea Plate subduction in Kyushu. We suggest that this, along with apparent invariance of radiated efficiency, suggests that an embrittlement process is more important in these regions than a thermal shear mechanism.

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Global rupture parameters for deep and intermediate‐depth earthquakes

Cited by 43 publications

References 53 publications

Energetic Onset of Earthquakes

Energetic Onset of Earthquakes

Complex and Diverse Rupture Processes of the 2018 Mw 8.2 and Mw 7.9 Tonga‐Fiji Deep Earthquakes

Source Parameter Variability of Intermediate‐Depth Earthquakes in Japanese Subduction Zones

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