FAILURE MAP
← Case archive

FA-71691 / Seismic magnitude estimation / Open access

Brune source radius and stress drop: radius cube · case 01

Stress drops carry units of force per length and are orders of magnitude off.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The radius is squared instead of cubed.

THE FAILURE

The radius is squared instead of cubed.

Unsuccessful approach: Cubing the diameter underestimates by eight.

Case contract

Seismic moment N*m, corner frequency Hz, shear velocity km/s; non-positive input returns None. r = 2.34 beta / (2 pi fc) in m; stress drop = 7/16 M0 / r^3 Pa. Return [r rounded 0.1 m, stress drop in MPa rounded 0.001].

Why this case matters

Stress drop characterises source physics and ground-motion scaling.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(m0_nm, fc_hz, beta_kms):
    if min(m0_nm, fc_hz, beta_kms) <= 0:
        return None
    r = 2.34 * beta_kms * 1000.0 / (2 * math.pi * fc_hz)
    ds = 7.0 / 16.0 * m0_nm / r ** 2
    return [round(r, 1), round(ds / 1e6, 3)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['M0 1.0e+12 fc 0.5 beta 3.2', [1000000000000.0, 0.5, 3.2], [2383.5, 0.0]], ['M0 1.0e+12 fc 0.5 beta 3.5', [1000000000000.0, 0.5, 3.5], [2607.0, 0.0]], ['M0 1.0e+12 fc 2.0 beta 3.2', [1000000000000.0, 2.0, 3.2], [595.9, 0.002]], ['M0 1.0e+12 fc 2.0 beta 3.5', [1000000000000.0, 2.0, 3.5], [651.7, 0.002]], ['M0 1.0e+12 fc 10.0 beta 3.2', [1000000000000.0, 10.0, 3.2], [119.2, 0.258]], ['M0 1.0e+12 fc 10.0 beta 3.5', [1000000000000.0, 10.0, 3.5], [130.3, 0.198]], ['M0 3.5e+14 fc 0.5 beta 3.2', [350000000000000.0, 0.5, 3.2], [2383.5, 0.011]], ['M0 3.5e+14 fc 0.5 beta 3.5', [350000000000000.0, 0.5, 3.5], [2607.0, 0.009]]], [['M0 1.0e+12 fc 2.0 beta 3.5', [1000000000000.0, 2.0, 3.5], [651.7, 0.002]], ['M0 3.5e+14 fc 0.5 beta 3.5', [350000000000000.0, 0.5, 3.5], [2607.0, 0.009]], ['M0 3.5e+14 fc 2.0 beta 3.2', [350000000000000.0, 2.0, 3.2], [595.9, 0.724]], ['M0 3.5e+14 fc 2.0 beta 3.5', [350000000000000.0, 2.0, 3.5], [651.7, 0.553]], ['M0 3.5e+14 fc 10.0 beta 3.2', [350000000000000.0, 10.0, 3.2], [119.2, 90.467]], ['M0 3.5e+14 fc 10.0 beta 3.5', [350000000000000.0, 10.0, 3.5], [130.3, 69.141]], ['M0 2.0e+17 fc 0.5 beta 3.2', [2e+17, 0.5, 3.2], [2383.5, 6.462]], ['M0 2.0e+17 fc 0.5 beta 3.5', [2e+17, 0.5, 3.5], [2607.0, 4.939]]], [['M0 1.0e+12 fc 0.5 beta 3.2', [1000000000000.0, 0.5, 3.2], [2383.5, 0.0]], ['M0 3.5e+14 fc 0.5 beta 3.2', [350000000000000.0, 0.5, 3.2], [2383.5, 0.011]], ['M0 2.0e+17 fc 0.5 beta 3.5', [2e+17, 0.5, 3.5], [2607.0, 4.939]], ['M0 2.0e+17 fc 2.0 beta 3.2', [2e+17, 2.0, 3.2], [595.9, 413.562]], ['M0 2.0e+17 fc 2.0 beta 3.5', [2e+17, 2.0, 3.5], [651.7, 316.072]], ['M0 2.0e+17 fc 10.0 beta 3.2', [2e+17, 10.0, 3.2], [119.2, 51695.192]], ['M0 2.0e+17 fc 10.0 beta 3.5', [2e+17, 10.0, 3.5], [130.3, 39508.992]], ['zero corner', [100000000000000.0, 0, 3.5], None]], [['M0 1.0e+12 fc 2.0 beta 3.2', [1000000000000.0, 2.0, 3.2], [595.9, 0.002]], ['M0 1.0e+12 fc 2.0 beta 3.5', [1000000000000.0, 2.0, 3.5], [651.7, 0.002]], ['M0 1.0e+12 fc 10.0 beta 3.2', [1000000000000.0, 10.0, 3.2], [119.2, 0.258]], ['M0 1.0e+12 fc 10.0 beta 3.5', [1000000000000.0, 10.0, 3.5], [130.3, 0.198]], ['M0 3.5e+14 fc 0.5 beta 3.2', [350000000000000.0, 0.5, 3.2], [2383.5, 0.011]], ['M0 3.5e+14 fc 0.5 beta 3.5', [350000000000000.0, 0.5, 3.5], [2607.0, 0.009]], ['M0 3.5e+14 fc 2.0 beta 3.2', [350000000000000.0, 2.0, 3.2], [595.9, 0.724]], ['M0 3.5e+14 fc 2.0 beta 3.5', [350000000000000.0, 2.0, 3.5], [651.7, 0.553]]], [['M0 3.5e+14 fc 0.5 beta 3.5', [350000000000000.0, 0.5, 3.5], [2607.0, 0.009]], ['M0 3.5e+14 fc 2.0 beta 3.5', [350000000000000.0, 2.0, 3.5], [651.7, 0.553]], ['M0 3.5e+14 fc 10.0 beta 3.2', [350000000000000.0, 10.0, 3.2], [119.2, 90.467]], ['M0 3.5e+14 fc 10.0 beta 3.5', [350000000000000.0, 10.0, 3.5], [130.3, 69.141]], ['M0 2.0e+17 fc 0.5 beta 3.2', [2e+17, 0.5, 3.2], [2383.5, 6.462]], ['M0 2.0e+17 fc 0.5 beta 3.5', [2e+17, 0.5, 3.5], [2607.0, 4.939]], ['M0 2.0e+17 fc 2.0 beta 3.2', [2e+17, 2.0, 3.2], [595.9, 413.562]], ['M0 2.0e+17 fc 2.0 beta 3.5', [2e+17, 2.0, 3.5], [651.7, 316.072]]]]
for label, args, expected in fixtures[N - 1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
M0 1.0e+12 fc 0.5 beta 3.2[2383.5, 0.077][2383.5, 0.0]Failed
M0 1.0e+12 fc 0.5 beta 3.5[2607.0, 0.064][2607.0, 0.0]Failed
M0 1.0e+12 fc 2.0 beta 3.2[595.9, 1.232][595.9, 0.002]Failed
M0 1.0e+12 fc 2.0 beta 3.5[651.7, 1.03][651.7, 0.002]Failed
M0 1.0e+12 fc 10.0 beta 3.2[119.2, 30.804][119.2, 0.258]Failed
M0 1.0e+12 fc 10.0 beta 3.5[130.3, 25.75][130.3, 0.198]Failed
M0 3.5e+14 fc 0.5 beta 3.2[2383.5, 26.953][2383.5, 0.011]Failed
M0 3.5e+14 fc 0.5 beta 3.5[2607.0, 22.531][2607.0, 0.009]Failed

SHA-256 / b2693f00a9ba8e06af37557d0393ebdb618e37eeb3f245f818ee8e5a96767bd2

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(m0_nm, fc_hz, beta_kms):
    if min(m0_nm, fc_hz, beta_kms) <= 0:
        return None
    r = 2.34 * beta_kms * 1000.0 / (2 * math.pi * fc_hz)
    ds = 7.0 / 16.0 * m0_nm / (2 * r) ** 3
    return [round(r, 1), round(ds / 1e6, 3)]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['M0 1.0e+12 fc 0.5 beta 3.2', [1000000000000.0, 0.5, 3.2], [2383.5, 0.0]], ['M0 1.0e+12 fc 0.5 beta 3.5', [1000000000000.0, 0.5, 3.5], [2607.0, 0.0]], ['M0 1.0e+12 fc 2.0 beta 3.2', [1000000000000.0, 2.0, 3.2], [595.9, 0.002]], ['M0 1.0e+12 fc 2.0 beta 3.5', [1000000000000.0, 2.0, 3.5], [651.7, 0.002]], ['M0 1.0e+12 fc 10.0 beta 3.2', [1000000000000.0, 10.0, 3.2], [119.2, 0.258]], ['M0 1.0e+12 fc 10.0 beta 3.5', [1000000000000.0, 10.0, 3.5], [130.3, 0.198]], ['M0 3.5e+14 fc 0.5 beta 3.2', [350000000000000.0, 0.5, 3.2], [2383.5, 0.011]], ['M0 3.5e+14 fc 0.5 beta 3.5', [350000000000000.0, 0.5, 3.5], [2607.0, 0.009]]], [['M0 1.0e+12 fc 2.0 beta 3.5', [1000000000000.0, 2.0, 3.5], [651.7, 0.002]], ['M0 3.5e+14 fc 0.5 beta 3.5', [350000000000000.0, 0.5, 3.5], [2607.0, 0.009]], ['M0 3.5e+14 fc 2.0 beta 3.2', [350000000000000.0, 2.0, 3.2], [595.9, 0.724]], ['M0 3.5e+14 fc 2.0 beta 3.5', [350000000000000.0, 2.0, 3.5], [651.7, 0.553]], ['M0 3.5e+14 fc 10.0 beta 3.2', [350000000000000.0, 10.0, 3.2], [119.2, 90.467]], ['M0 3.5e+14 fc 10.0 beta 3.5', [350000000000000.0, 10.0, 3.5], [130.3, 69.141]], ['M0 2.0e+17 fc 0.5 beta 3.2', [2e+17, 0.5, 3.2], [2383.5, 6.462]], ['M0 2.0e+17 fc 0.5 beta 3.5', [2e+17, 0.5, 3.5], [2607.0, 4.939]]], [['M0 1.0e+12 fc 0.5 beta 3.2', [1000000000000.0, 0.5, 3.2], [2383.5, 0.0]], ['M0 3.5e+14 fc 0.5 beta 3.2', [350000000000000.0, 0.5, 3.2], [2383.5, 0.011]], ['M0 2.0e+17 fc 0.5 beta 3.5', [2e+17, 0.5, 3.5], [2607.0, 4.939]], ['M0 2.0e+17 fc 2.0 beta 3.2', [2e+17, 2.0, 3.2], [595.9, 413.562]], ['M0 2.0e+17 fc 2.0 beta 3.5', [2e+17, 2.0, 3.5], [651.7, 316.072]], ['M0 2.0e+17 fc 10.0 beta 3.2', [2e+17, 10.0, 3.2], [119.2, 51695.192]], ['M0 2.0e+17 fc 10.0 beta 3.5', [2e+17, 10.0, 3.5], [130.3, 39508.992]], ['zero corner', [100000000000000.0, 0, 3.5], None]], [['M0 1.0e+12 fc 2.0 beta 3.2', [1000000000000.0, 2.0, 3.2], [595.9, 0.002]], ['M0 1.0e+12 fc 2.0 beta 3.5', [1000000000000.0, 2.0, 3.5], [651.7, 0.002]], ['M0 1.0e+12 fc 10.0 beta 3.2', [1000000000000.0, 10.0, 3.2], [119.2, 0.258]], ['M0 1.0e+12 fc 10.0 beta 3.5', [1000000000000.0, 10.0, 3.5], [130.3, 0.198]], ['M0 3.5e+14 fc 0.5 beta 3.2', [350000000000000.0, 0.5, 3.2], [2383.5, 0.011]], ['M0 3.5e+14 fc 0.5 beta 3.5', [350000000000000.0, 0.5, 3.5], [2607.0, 0.009]], ['M0 3.5e+14 fc 2.0 beta 3.2', [350000000000000.0, 2.0, 3.2], [595.9, 0.724]], ['M0 3.5e+14 fc 2.0 beta 3.5', [350000000000000.0, 2.0, 3.5], [651.7, 0.553]]], [['M0 3.5e+14 fc 0.5 beta 3.5', [350000000000000.0, 0.5, 3.5], [2607.0, 0.009]], ['M0 3.5e+14 fc 2.0 beta 3.5', [350000000000000.0, 2.0, 3.5], [651.7, 0.553]], ['M0 3.5e+14 fc 10.0 beta 3.2', [350000000000000.0, 10.0, 3.2], [119.2, 90.467]], ['M0 3.5e+14 fc 10.0 beta 3.5', [350000000000000.0, 10.0, 3.5], [130.3, 69.141]], ['M0 2.0e+17 fc 0.5 beta 3.2', [2e+17, 0.5, 3.2], [2383.5, 6.462]], ['M0 2.0e+17 fc 0.5 beta 3.5', [2e+17, 0.5, 3.5], [2607.0, 4.939]], ['M0 2.0e+17 fc 2.0 beta 3.2', [2e+17, 2.0, 3.2], [595.9, 413.562]], ['M0 2.0e+17 fc 2.0 beta 3.5', [2e+17, 2.0, 3.5], [651.7, 316.072]]]]
for label, args, expected in fixtures[N - 1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
M0 1.0e+12 fc 0.5 beta 3.2[2383.5, 0.0][2383.5, 0.0]Passed
M0 1.0e+12 fc 0.5 beta 3.5[2607.0, 0.0][2607.0, 0.0]Passed
M0 1.0e+12 fc 2.0 beta 3.2[595.9, 0.0][595.9, 0.002]Failed
M0 1.0e+12 fc 2.0 beta 3.5[651.7, 0.0][651.7, 0.002]Failed
M0 1.0e+12 fc 10.0 beta 3.2[119.2, 0.032][119.2, 0.258]Failed
M0 1.0e+12 fc 10.0 beta 3.5[130.3, 0.025][130.3, 0.198]Failed
M0 3.5e+14 fc 0.5 beta 3.2[2383.5, 0.001][2383.5, 0.011]Failed
M0 3.5e+14 fc 0.5 beta 3.5[2607.0, 0.001][2607.0, 0.009]Failed

SHA-256 / 4984ca90a76cfe2e239bda534bdcec2b3b48974fe8c29ad8ce17e57fca4eb93c

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 8 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

Member access is invitation-based. Sign in with your invited account to inspect the repair.

Sign in to the archive ↗

Verification & scope

Stipulated deterministic teaching model of a seismological magnitude procedure; constants and tables are fixed by the contract and no claim of agency or standards conformance is made. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:48:31.884003+00:00.

Case digest / 0d54ddae6b9b8f9ff161f3d119e0dfe79a8fa3f9971697654b252ebbde84048f