ETAS Binary Analysis Report

Table Of Contents

• Simulation Configuration
• Primary Aftershock
  • Occurrence Timeline
• Catalog Matches
• Primary Aftershock Timing
• Catalog Map Plots
  • Individual Simulated Catalog Maps
• Ruptures on Hollywood fault
• Ruptures on Raymond fault
• Ruptures on Hollywood, Raymond faults
• JSON Input File

Simulation Configuration

• Simulation Start Time: 2026-10-15 10:15:00.000

• Simulation Duration: 365d 06h 00m 00.000s

• Number of Simulations: 1000000

• ETAS Config JSON: /Users/bhatthal/Downloads/Merged-FSS_Rupture_201887_M7p8_Start_2026_10_15_1_yr_kCOV_1p5_MaxPtSrcM_6/config.json

• Fault System Solution ZIP: /Users/bhatthal/git/ucerf3-etas-launcher/inputs/2013_05_10-ucerf3p3-production-10runs_COMPOUND_SOL_FM3_1_SpatSeisU3_MEAN_BRANCH_AVG_SOL.zip

• Binary Results: /Users/bhatthal/Downloads/Merged-FSS_Rupture_201887_M7p8_Start_2026_10_15_1_yr_kCOV_1p5_MaxPtSrcM_6/results_m5_preserve_chain.bin

Primary Aftershock

• FSS Index: 218331

• Magnitude: M6.9221

• Significance threshold for simulation count: M2.5

• Total number of simulations: 1000000

• Number of M≥2.5 simulations: 992834

• Number of simulations with this aftershock: 40

• Probability over all 1000000 simulations: 4.00E-5 (0.00%)

• Probability over 992834 significant (M≥2.5) simulations: 4.03E-5 (0.00%)

A "significant" simulation is one that produced at least one M≥2.5 rupture anywhere in the simulation domain; it is the appropriate denominator when comparing against observed aftershock statistics, since simulations that produced no detectable seismicity cannot meaningfully count toward the probability of a specific rupture.

Both probabilities are reported because the raw-binned probability (over all N simulations) is the more conservative (lower) number, while the conditional probability over significant simulations is what most seismic-hazard analyses quote.

Occurrence Timeline

Cumulative rupture occurrences over time across all catalogs, binned by time after the simulation start. Each bar's height is the running total of ruptures through that bin: other M≥2.5 ruptures (gray) stacked beneath the scenario rupture (red).

Catalog Matches

The following table summarizes all 40 catalogs where the primary aftershock occurred.

Parent-section ruptures — for each matching catalog, the number of distinct ruptures in that catalog whose rupture surface intersects the listed parent section(s). Each entry is label:count; labels are compact codes (the first letter of each parent section, joined by +): H = Hollywood, R = Raymond, H+R = Hollywood, Raymond. These counts overlap and are not a partition: a rupture whose surface spans multiple parent sections is counted under every combination it intersects, so a multi-section rupture appears in several entries and the counts should not be summed (e.g. a rupture crossing both H and R also appears under H+R).

Across all 40 matching catalogs, the scenario rupture occurred between 2026-10-15 10:38:28.219 and 2027-09-29 10:50:11.748 (Δt after sim start: 0d 00h 23m 28.219s–349d 00h 35m 11.748s); catalog size ranged from 22 to 1232 ruptures (mean 232.3).

Primary Aftershock Timing

Cumulative count of matching catalogs that had produced the primary aftershock by each time after the simulation start, across the 40 matching catalogs. The final bar reaches 40 (every matching catalog contains the primary aftershock within the simulation duration).

Number of matching catalogs where the primary aftershock occurred within:

• Under 1 hour: 1 (2.50%)
• Under 1 day: 5 (12.50%)
• Under 1 week: 14 (35.00%)
• Under 1 month: 21 (52.50%)
• Under 1 year: 40 (100.00%)

Catalog Map Plots

Individual Simulated Catalog Maps

These are map plots of individual catalogs from the simulations, selected as the closest catalog to each of the given percentiles in terms of total number of events.

Duration	p0.0 %-ile	p25.0 %-ile	p50.0 %-ile	p75.0 %-ile	p97.5 %-ile
1 Week
1 Month
1 Year

The above plots only consider the 40 catalogs which matched the scenario description.

Ruptures on Hollywood fault

Found 1392 aftershocks over these parent sections across 1000000 simulated catalogs (0.14%).

Ruptures on Raymond fault

Found 3387 aftershocks over these parent sections across 1000000 simulated catalogs (0.34%).

Ruptures on Hollywood, Raymond faults

Found 1090 aftershocks over these parent sections across 1000000 simulated catalogs (0.11%).

JSON Input File

{
  "numSimulations": 1000000,
  "duration": 1.0,
  "startTimeMillis": 1792084500000,
  "includeSpontaneous": false,
  "randomSeed": 1779919217729,
  "binaryOutput": true,
  "binaryOutputFilters": [
    {
      "prefix": "results_complete",
      "descendantsOnly": false
    },
    {
      "prefix": "results_m5_preserve_chain",
      "minMag": 5.0,
      "preserveChainBelowMag": true,
      "descendantsOnly": false
    }
  ],
  "forceRecalc": false,
  "simulationName": "FSS Rupture 201887, M7.8, Start 2026/10/15, 1 yr, kCOV\u003d1.5, MaxPtSrcM\u003d6",
  "numRetries": 3,
  "outputDir": "${ETAS_SIM_DIR}/2026_05_27-FSS_Rupture_201887_M7p8_Start_2026_10_15_1_yr_kCOV_1p5_MaxPtSrcM_6",
  "treatTriggerCatalogAsSpontaneous": false,
  "triggerRuptures": [
    {
      "fssIndex": 201887,
      "mag": 7.8
    }
  ],
  "cacheDir": "${ETAS_LAUNCHER}/inputs/cache_fm3p1_ba",
  "fssFile": "${ETAS_LAUNCHER}/inputs/2013_05_10-ucerf3p3-production-10runs_COMPOUND_SOL_FM3_1_SpatSeisU3_MEAN_BRANCH_AVG_SOL.zip",
  "probModel": "FULL_TD",
  "applySubSeisForSupraNucl": true,
  "totRateScaleFactor": 1.29,
  "gridSeisCorr": true,
  "timeIndependentERF": false,
  "griddedOnly": false,
  "imposeGR": false,
  "includeIndirectTriggering": true,
  "gridSeisDiscr": 0.1,
  "catalogCompletenessModel": "RELAXED",
  "etas_k_cov": 1.5,
  "maxPointSourceMag": 6.0,
  "configCommand": "u3etas_config_builder.sh --start-time 1792084500000 --fss-index 201887 --magnitude 7.8 --num-simulations 500000 --duration-years 1 --hpc-site USC_CARC --nodes 36 --hours 24 --queue scec --etas-k-cov 1.5 --max-point-src-mag 6",
  "configTime": 1779919217729
}