10:45 〜 12:15
[SSS11-P03] Megathrust and significant earthquake predictions with Physical Wavelets
キーワード：Scale dependent earthquake phenomena, Deterministic earthquake predictions, Physical Wavelets
Physical Wavelets (PWs) can describe the megathrust and significant earthquake (EQ) genesis processes to predict their focuses, fault movements, sizes, and rupture times up to three months in advance [1-4]. The time accuracies are within a day by real-time monitoring of the expected rupture processes.
Scale-dependent EQ phenomena
The Earth's lithosphere is a three-layer system of the brittle (B) upper crust, the ductile (D) lower crust, and the D uppermost mantle. The plate-driving forces create steady-state creep in the D parts, building up the stress in the B part through the D-B transition region by coupling the three layers [5]. If the ductile strain rate is high, the creep deformation generates EQs of various sizes in the B upper crust. The stress state is a so-called frictional failure whose principal components are vertical and horizontal [5]. The seismic activities appear chaotic and complex. However, the well-known EQ size-frequency distributions of foreshocks and aftershocks of the 2011 Tohoku M9 EQ show a subtle depth dependence of the D-B transition region [3]. The M9 EQ genesis process has a scale dependence [1-4].
Deterministic predictions
The PWs describe the scale dependence as an equation of how the principal stress changes generate significant and megathrust EQs in every mesh size of about 4o by 5o throughout Japan. The equation in each mesh describes the consecutive EQ events as a virtual EQ particle motion under the crustal stress changes. The mesh size and shape are selective, and it may be a small or large region covered by a seismic network. Each EQ event in a mesh detected by the seismic network has the property of the focus (in latitude LAT, longitude LON, and depth DEP), its origin time (event time), and magnitude MAG. They are the so-called EQ source parameters. The interval between consecutive event times is the inter-event interval (INT). In the c-coordinate space (c = LAT, LON, DEP, INT, and MAG), an event is the virtual EQ particle of unit mass that emerges and moves to a new location at the next event. A time history of the movement is {c}={d (c, 1 ), ., d (c, m ), ., d(c, N)}. The d (c, m) is the particle position at time m that is the chronological event index m having no INT at m = 0. The d (c, N) is the last observed position. The movement is stochastic, like a Brownian particle [6]. However, d (c, m) is a function of the principal stress components for which a selection of MAG ≧ Mc (Mc ≈ 3.5) reduces the stochastic noise level to about 15 - 25 % [3].
The {c} may be a displacement time series from a reference, as shown in Fig. 1, where noisy d (c, m ) is in green. The cross-correlation of PWs with the {c} defines the noise-free displacement D (c, τ) in red and acceleration A (c, τ) in blue or black at time τ, expressing the EQ scale-dependent phenomena by a periodic equation of A(c, τ) = −K(c)×D (c, τ) with a positive constant K(c) at time τ. K(c) weakly depends on time τ. The A (c, τ) shows significant and megathrust EQ genesis processes of CQK and CQT as in Fig.1, named after Kobe M7.2 and Tottori M7.2, respectively [1,3,4].
The A (c, τ) and D (c, τ), along with the strain-energy accumulation-release cycle and GPS analyses during CQK or CQT, can predict the fault sizes and movements, the rupture times, and the focuses of imminent significant and megathrust EQs [1-4]. At present, any other tool cannot locate and extract the scale-dependent and deterministic evolution of the principal stress components to significant and megathrust EQs.
[1] Takeda, F. (2015) https://patents.google.com/patent/JP5798545B2/ja
[2] Takeda, F. (2021) https://doi.org/10.48550/arXiv.2107.02799
[3] Takeda, F. (2022) https://doi.org/10.48550/arXiv.2201.02815
[4] Takeda, F. (2022) https://doi.org/10.48550/arXiv.2208.09486
[5] Zoback, M. D., and Zoback, M. L. (2002) State of stress in the Earth's lithosphere, IHE & Eng. Seismology, Academic Press, 559-568
[6] Takeo, M. (1999) Disperse systems, Wiley-VCH
Scale-dependent EQ phenomena
The Earth's lithosphere is a three-layer system of the brittle (B) upper crust, the ductile (D) lower crust, and the D uppermost mantle. The plate-driving forces create steady-state creep in the D parts, building up the stress in the B part through the D-B transition region by coupling the three layers [5]. If the ductile strain rate is high, the creep deformation generates EQs of various sizes in the B upper crust. The stress state is a so-called frictional failure whose principal components are vertical and horizontal [5]. The seismic activities appear chaotic and complex. However, the well-known EQ size-frequency distributions of foreshocks and aftershocks of the 2011 Tohoku M9 EQ show a subtle depth dependence of the D-B transition region [3]. The M9 EQ genesis process has a scale dependence [1-4].
Deterministic predictions
The PWs describe the scale dependence as an equation of how the principal stress changes generate significant and megathrust EQs in every mesh size of about 4o by 5o throughout Japan. The equation in each mesh describes the consecutive EQ events as a virtual EQ particle motion under the crustal stress changes. The mesh size and shape are selective, and it may be a small or large region covered by a seismic network. Each EQ event in a mesh detected by the seismic network has the property of the focus (in latitude LAT, longitude LON, and depth DEP), its origin time (event time), and magnitude MAG. They are the so-called EQ source parameters. The interval between consecutive event times is the inter-event interval (INT). In the c-coordinate space (c = LAT, LON, DEP, INT, and MAG), an event is the virtual EQ particle of unit mass that emerges and moves to a new location at the next event. A time history of the movement is {c}={d (c, 1 ), ., d (c, m ), ., d(c, N)}. The d (c, m) is the particle position at time m that is the chronological event index m having no INT at m = 0. The d (c, N) is the last observed position. The movement is stochastic, like a Brownian particle [6]. However, d (c, m) is a function of the principal stress components for which a selection of MAG ≧ Mc (Mc ≈ 3.5) reduces the stochastic noise level to about 15 - 25 % [3].
The {c} may be a displacement time series from a reference, as shown in Fig. 1, where noisy d (c, m ) is in green. The cross-correlation of PWs with the {c} defines the noise-free displacement D (c, τ) in red and acceleration A (c, τ) in blue or black at time τ, expressing the EQ scale-dependent phenomena by a periodic equation of A(c, τ) = −K(c)×D (c, τ) with a positive constant K(c) at time τ. K(c) weakly depends on time τ. The A (c, τ) shows significant and megathrust EQ genesis processes of CQK and CQT as in Fig.1, named after Kobe M7.2 and Tottori M7.2, respectively [1,3,4].
The A (c, τ) and D (c, τ), along with the strain-energy accumulation-release cycle and GPS analyses during CQK or CQT, can predict the fault sizes and movements, the rupture times, and the focuses of imminent significant and megathrust EQs [1-4]. At present, any other tool cannot locate and extract the scale-dependent and deterministic evolution of the principal stress components to significant and megathrust EQs.
[1] Takeda, F. (2015) https://patents.google.com/patent/JP5798545B2/ja
[2] Takeda, F. (2021) https://doi.org/10.48550/arXiv.2107.02799
[3] Takeda, F. (2022) https://doi.org/10.48550/arXiv.2201.02815
[4] Takeda, F. (2022) https://doi.org/10.48550/arXiv.2208.09486
[5] Zoback, M. D., and Zoback, M. L. (2002) State of stress in the Earth's lithosphere, IHE & Eng. Seismology, Academic Press, 559-568
[6] Takeo, M. (1999) Disperse systems, Wiley-VCH