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Copy file name to clipboardExpand all lines: README.md
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@@ -8,34 +8,36 @@ the Japanese JMA instrumental seismic intensity (Shindo) scale. Following the
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probabilistic inverse theory of Tarantola (2005), it fully accounts for uncertainties
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in both the measured data (seismic intensity) and the theoretical model (ground motion
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prediction equation, GMPE). The system evaluates the posterior Probability Density
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Function (PDF) for the epicenter location and magnitude via an exhaustive 3D grid
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search, ensuring no local minima are missed. By leveraging JAX for massive parallelization,
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Function (PDF) for the epicenter location and magnitude via an exhaustive 3D grid search,
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ensuring no local minima are missed. By leveraging JAX for massive parallelization, modern
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it allows for near-instantaneous evaluation on both CPU and GPU, making it ideal for both
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modern real-time seismology and the processing of large-scale historical earthquake catalogs.
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**Key Features:**
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***HPC Ready:** Fully vectorized backend using JAX (XLA) with seamless support for GPU/TPU acceleration.
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real-time seismology and the processing of large-scale historical earthquake catalogs. Key Features:
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***HPC Ready:** Fully vectorized backend using JAX (XLA) with seamless support for CPU/GPU/TPU acceleration.
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***Bayesian Framework:** Complete 3D PDF evaluation accounting for both observational uncertainties and modeling errors.
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***Scientific GMPE:** Implements the Morikawa & Fujiwara (2013) Ground Motion Prediction Equation for forward computation.
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***Automatic Site Effects:** Integrated workflow for automated V<sub>S30</sub> retrieval from a high-resolution J-SHIS-derived SQL database for Japan (for sites without V<sub>S30</sub> measurements).
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***Automatic Site Effects:** Integrated workflow for automated V<sub>S30</sub> retrieval from a high-resolution J-SHIS-derived SQL database for Japan (for sites in Japan without direct V<sub>S30</sub> measurements).
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***Historical & Modern Data:** Support for both recent instrumental records and macroseismic (historical) observations.
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***User-Friendly:** Simple ASCII input/output, PEP8 compliant, and structured for researchers and Python-beginners.
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1 METHODOLOGY
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===================
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The inversion follows the probabilistic inverse theory and total error budget
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accounting for both observational and theoretical uncertainties as described in:
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accounting for both observational and theoretical uncertainties as described in Tarantola (2005).
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The JMA intensity prediction is following Morikawa and Fujiwara (2013).
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Tarantola, A. (2005, Chapter 7.1). Inverse Problem Theory and Methods
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for Model Parameter Estimation, Society for Industrial and Applied
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Mathematics, Philadelphia, USA.
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Morikawa, N., Fujiwara, H. (2013). A New Ground Motion Prediction Equation
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for Japan Applicable up to M9 Mega-Earthquake, J. Disaster Res., 8(5), 878-888. [https://doi.org/10.20965/jdr.2013.p0878](https://doi.org/10.20965/jdr.2013.p0878)
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2 DATABASE (SQLite)
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===================
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If missing V<sub>S30</sub> values are detected, the system automatically interfaces with an
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optimized SQLite subset of the J-SHIS-derived database for Japan:
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optimized SQLite subset of the J-SHIS-derived database for Japan (Hallo, 2026):
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Hallo, M. (2026). Research Dataset: Optimized Site Parameters (Vs30)
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for Seismic Hazard Analysis in Japan (derived from J-SHIS) [Data set].
The computational engine is engineered for maximum throughput by bypassing standard Python execution loops in favor of **XLA (Accelerated Linear Algebra)**:
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***JIT Compilation:** Every critical path—from the Forward GMPE evaluation to the Likelihood summation—is Just-In-Time (JIT) compiled. This transforms Python code into optimized machine code tailored for the specific hardware (CPU or GPU).
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***JIT Compilation:** Every critical path, from the Forward GMPE evaluation to the Likelihood summation, is Just-In-Time (JIT) compiled. This transforms Python code into optimized machine code tailored for the specific hardware (CPU or GPU).
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***Multi-Device Scaling:** Leveraging JAX allows the 3D grid-search to be offloaded to GPU/TPU without code changes. On multi-core CPUs, it utilizes all available threads via vectorized operations rather than standard multiprocessing.
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***Vectorized Grid Search:** Instead of iterative loops, the framework uses nested vectorization (`vmap`). The 3D parameter space is treated as a high-dimensional tensor, allowing the hardware to evaluate thousands of potential epicenters and magnitudes in a single clock cycle.
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***SQLite Spatial Indexing:** Automatic retrieval is powered by a high-performance SQLite backend. This allows for rapid spatial lookups within a processed database, ensuring that even datasets with missing site data are enriched with industry-standard values.
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[*] SUCCESS: All done
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```
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Regarding the results, the figure below illustrates the output 3D posterior Probability Density Function (PDF) with orthogonal slices (Mw, N-S, E-W) passing through the Maximum Likelihood (ML) location.
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Regarding the results, the figure below illustrates the output 3D posterior Probability Density Function (PDF) with orthogonal slices (M<sub>w</sub>, N-S, E-W) passing through the Maximum Likelihood (ML) solution.
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