FA-71531 / Seismic magnitude estimation / Open access

Epicentral distance and station selection: latitude cosine units · case 01

East-west distances are wildly wrong while north-south ones are fine.

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

ROOT CAUSE

The cosine factors are evaluated on latitudes in degrees.

VERIFIED REPAIR

Use cos of the latitudes in radians.

Unsuccessful approach: cos(dphi) is not the product of the latitude cosines.

Case contract

event [lat, lon] and stations [code, lat, lon] in degrees. Haversine distance with R = 6371 km. Keep stations within 600 km inclusive. Return [[code, km rounded 0.1, degrees rounded 0.001]] sorted by distance then code.

Why this case matters

Local magnitude and location use only stations in the calibrated distance range.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(event, stations):
    R = 6371.0
    out = []
    for code, la, lo in stations:
        p1 = math.radians(event[0])
        p2 = math.radians(la)
        dphi = p2 - p1
        dl = math.radians(lo - event[1])
        a = math.sin(dphi / 2) ** 2 + math.cos(event[0]) * math.cos(la) * math.sin(dl / 2) ** 2
        d = 2 * R * math.asin(math.sqrt(min(1.0, a)))
        if d <= 600:
            out.append([code, round(d, 1), round(math.degrees(d / R), 3)])
    return sorted(out, key=lambda r: (r[1], r[0]))
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['network 2', [[44.56, -117.35], [['S00', 33.87, -122.39], ['S01', 32.58, -119.0], ['S02', 30.34, -116.47], ['S03', 43.88, -121.21], ['S04', 32.47, -111.54]]], [['S03', 316.7, 2.848]]], ['network 3', [[37.38, -120.81], [['S00', 37.99, -119.17], ['S01', 44.87, -121.53], ['S02', 36.92, -112.06], ['S03', 45.59, -124.41], ['S04', 48.41, -124.22], ['S05', 45.33, -114.43]]], [['S00', 159.5, 1.434]]], ['network 5', [[41.23, -114.32], [['S00', 48.44, -112.36], ['S01', 39.92, -111.66], ['S02', 31.63, -118.69], ['S03', 44.86, -116.63], ['S04', 45.92, -112.0], ['S05', 31.93, -116.6]]], [['S01', 267.7, 2.408], ['S03', 445.1, 4.003], ['S04', 553.9, 4.981]]], ['network 6', [[42.93, -114.98], [['S00', 41.78, -113.99], ['S01', 46.04, -120.17], ['S02', 39.37, -111.82], ['S03', 48.06, -111.76], ['S04', 45.02, -119.59]]], [['S00', 151.6, 1.363], ['S04', 435.9, 3.92], ['S02', 476.0, 4.281], ['S01', 537.5, 4.834]]], ['network 7', [[38.24, -116.31], [['S00', 44.82, -111.25], ['S01', 41.96, -117.22], ['S02', 45.77, -122.79]]], [['S01', 420.8, 3.784]]], ['network 8', [[37.27, -120.03], [['S00', 32.27, -124.77], ['S01', 36.2, -116.4], ['S02', 46.93, -122.1], ['S03', 48.81, -114.9]]], [['S01', 344.6, 3.099]]], ['network 9', [[39.63, -120.96], [['S00', 47.23, -111.26], ['S01', 41.57, -124.4], ['S02', 43.29, -122.87], ['S03', 45.0, -116.27], ['S04', 49.12, -110.82], ['S05', 33.21, -123.87]]], [['S01', 361.7, 3.253], ['S02', 437.0, 3.93]]], ['network 12', [[39.75, -115.38], [['S00', 39.91, -122.96], ['S01', 40.0, -124.22], ['S02', 45.24, -114.12], ['S03', 36.65, -117.11], ['S04', 39.11, -115.83], ['S05', 48.17, -111.51]]], [['S04', 81.0, 0.728], ['S03', 376.4, 3.385]]]], [['network 6', [[42.93, -114.98], [['S00', 41.78, -113.99], ['S01', 46.04, -120.17], ['S02', 39.37, -111.82], ['S03', 48.06, -111.76], ['S04', 45.02, -119.59]]], [['S00', 151.6, 1.363], ['S04', 435.9, 3.92], ['S02', 476.0, 4.281], ['S01', 537.5, 4.834]]], ['network 9', [[39.63, -120.96], [['S00', 47.23, -111.26], ['S01', 41.57, -124.4], ['S02', 43.29, -122.87], ['S03', 45.0, -116.27], ['S04', 49.12, -110.82], ['S05', 33.21, -123.87]]], [['S01', 361.7, 3.253], ['S02', 437.0, 3.93]]], ['network 12', [[39.75, -115.38], [['S00', 39.91, -122.96], ['S01', 40.0, -124.22], ['S02', 45.24, -114.12], ['S03', 36.65, -117.11], ['S04', 39.11, -115.83], ['S05', 48.17, -111.51]]], [['S04', 81.0, 0.728], ['S03', 376.4, 3.385]]], ['network 14', [[36.07, -121.76], [['S00', 47.41, -116.96], ['S01', 36.95, -119.89], ['S02', 31.53, -122.92], ['S03', 32.44, -118.51], ['S04', 35.33, -113.8]]], [['S01', 193.7, 1.742], ['S03', 502.1, 4.515], ['S02', 516.1, 4.641]]], ['network 16', [[38.62, -114.83], [['S00', 44.48, -122.4], ['S01', 39.21, -110.38]]], [['S01', 390.5, 3.512]]], ['network 17', [[40.22, -115.43], [['S00', 34.58, -110.93], ['S01', 32.33, -116.94], ['S02', 42.07, -117.12]]], [['S02', 249.7, 2.245]]], ['network 18', [[36.81, -120.08], [['S00', 45.93, -122.19], ['S01', 42.64, -115.55], ['S02', 44.75, -122.18], ['S03', 41.26, -115.09], ['S04', 43.24, -121.66]]], []], ['network 20', [[44.06, -114.59], [['S00', 39.32, -110.59], ['S01', 36.71, -114.59], ['S02', 38.77, -120.99], ['S03', 31.6, -120.79]]], []]], [['network 9', [[39.63, -120.96], [['S00', 47.23, -111.26], ['S01', 41.57, -124.4], ['S02', 43.29, -122.87], ['S03', 45.0, -116.27], ['S04', 49.12, -110.82], ['S05', 33.21, -123.87]]], [['S01', 361.7, 3.253], ['S02', 437.0, 3.93]]], ['network 23', [[44.25, -117.92], [['S00', 44.39, -122.69], ['S01', 37.18, -114.68], ['S02', 44.85, -124.42], ['S03', 42.91, -119.64]]], [['S03', 203.5, 1.83], ['S00', 379.7, 3.415], ['S02', 519.2, 4.67]]], ['network 24', [[42.12, -121.58], [['S00', 39.06, -115.35], ['S01', 41.41, -121.4]]], [['S01', 80.3, 0.723]]], ['network 25', [[38.77, -114.31], [['S00', 43.94, -110.09], ['S01', 47.99, -124.55], ['S02', 48.6, -124.13], ['S03', 47.11, -121.53]]], []], ['network 26', [[42.47, -114.8], [['S00', 36.7, -111.1], ['S01', 46.83, -118.43], ['S02', 34.65, -112.02]]], [['S01', 563.3, 5.066]]], ['network 28', [[36.13, -121.64], [['S00', 30.99, -116.87], ['S01', 48.63, -114.1], ['S02', 30.53, -117.85], ['S03', 31.41, -124.62], ['S04', 35.71, -124.61]]], [['S04', 271.5, 2.442], ['S03', 592.6, 5.33]]], ['co-located station', [[40.0, -120.0], [['AAA', 40.0, -120.0], ['BBB', 41.0, -120.0]]], [['AAA', 0.0, 0.0], ['BBB', 111.2, 1.0]]], ['equal distance tie', [[0.0, 0.0], [['ZZZ', 1.0, 0.0], ['AAA', -1.0, 0.0]]], [['AAA', 111.2, 1.0], ['ZZZ', 111.2, 1.0]]]], [['network 2', [[44.56, -117.35], [['S00', 33.87, -122.39], ['S01', 32.58, -119.0], ['S02', 30.34, -116.47], ['S03', 43.88, -121.21], ['S04', 32.47, -111.54]]], [['S03', 316.7, 2.848]]], ['network 3', [[37.38, -120.81], [['S00', 37.99, -119.17], ['S01', 44.87, -121.53], ['S02', 36.92, -112.06], ['S03', 45.59, -124.41], ['S04', 48.41, -124.22], ['S05', 45.33, -114.43]]], [['S00', 159.5, 1.434]]], ['network 5', [[41.23, -114.32], [['S00', 48.44, -112.36], ['S01', 39.92, -111.66], ['S02', 31.63, -118.69], ['S03', 44.86, -116.63], ['S04', 45.92, -112.0], ['S05', 31.93, -116.6]]], [['S01', 267.7, 2.408], ['S03', 445.1, 4.003], ['S04', 553.9, 4.981]]], ['network 6', [[42.93, -114.98], [['S00', 41.78, -113.99], ['S01', 46.04, -120.17], ['S02', 39.37, -111.82], ['S03', 48.06, -111.76], ['S04', 45.02, -119.59]]], [['S00', 151.6, 1.363], ['S04', 435.9, 3.92], ['S02', 476.0, 4.281], ['S01', 537.5, 4.834]]], ['network 7', [[38.24, -116.31], [['S00', 44.82, -111.25], ['S01', 41.96, -117.22], ['S02', 45.77, -122.79]]], [['S01', 420.8, 3.784]]], ['network 8', [[37.27, -120.03], [['S00', 32.27, -124.77], ['S01', 36.2, -116.4], ['S02', 46.93, -122.1], ['S03', 48.81, -114.9]]], [['S01', 344.6, 3.099]]], ['network 9', [[39.63, -120.96], [['S00', 47.23, -111.26], ['S01', 41.57, -124.4], ['S02', 43.29, -122.87], ['S03', 45.0, -116.27], ['S04', 49.12, -110.82], ['S05', 33.21, -123.87]]], [['S01', 361.7, 3.253], ['S02', 437.0, 3.93]]], ['network 16', [[38.62, -114.83], [['S00', 44.48, -122.4], ['S01', 39.21, -110.38]]], [['S01', 390.5, 3.512]]]], [['network 8', [[37.27, -120.03], [['S00', 32.27, -124.77], ['S01', 36.2, -116.4], ['S02', 46.93, -122.1], ['S03', 48.81, -114.9]]], [['S01', 344.6, 3.099]]], ['network 12', [[39.75, -115.38], [['S00', 39.91, -122.96], ['S01', 40.0, -124.22], ['S02', 45.24, -114.12], ['S03', 36.65, -117.11], ['S04', 39.11, -115.83], ['S05', 48.17, -111.51]]], [['S04', 81.0, 0.728], ['S03', 376.4, 3.385]]], ['network 14', [[36.07, -121.76], [['S00', 47.41, -116.96], ['S01', 36.95, -119.89], ['S02', 31.53, -122.92], ['S03', 32.44, -118.51], ['S04', 35.33, -113.8]]], [['S01', 193.7, 1.742], ['S03', 502.1, 4.515], ['S02', 516.1, 4.641]]], ['network 16', [[38.62, -114.83], [['S00', 44.48, -122.4], ['S01', 39.21, -110.38]]], [['S01', 390.5, 3.512]]], ['network 17', [[40.22, -115.43], [['S00', 34.58, -110.93], ['S01', 32.33, -116.94], ['S02', 42.07, -117.12]]], [['S02', 249.7, 2.245]]], ['network 18', [[36.81, -120.08], [['S00', 45.93, -122.19], ['S01', 42.64, -115.55], ['S02', 44.75, -122.18], ['S03', 41.26, -115.09], ['S04', 43.24, -121.66]]], []], ['network 20', [[44.06, -114.59], [['S00', 39.32, -110.59], ['S01', 36.71, -114.59], ['S02', 38.77, -120.99], ['S03', 31.6, -120.79]]], []], ['network 23', [[44.25, -117.92], [['S00', 44.39, -122.69], ['S01', 37.18, -114.68], ['S02', 44.85, -124.42], ['S03', 42.91, -119.64]]], [['S03', 203.5, 1.83], ['S00', 379.7, 3.415], ['S02', 519.2, 4.67]]]]]
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 fixture	Actual	Expected	Outcome
network 2	`[['S03', 399.0, 3.589]]`	`[['S03', 316.7, 2.848]]`	Failed
network 3	`[['S00', 186.7, 1.679]]`	`[['S00', 159.5, 1.434]]`	Failed
network 5	`[['S01', 265.0, 2.383], ['S03', 352.0, 3.166], ['S04', 542.3, 4.877]]`	`[['S01', 267.7, 2.408], ['S03', 445.1, 4.003], ['S04', 553.9, 4.981]]`	Failed
network 6	`[['S00', 113.2, 1.018], ['S01', 205.9, 1.852], ['S04', 346.7, 3.118], ['S02', 388.1, 3.49], ['S03', 536.4, 4.824]]`	`[['S00', 151.6, 1.363], ['S04', 435.9, 3.92], ['S02', 476.0, 4.281], ['S01', 537.5, 4.834]]`	Failed
network 7	`[['S01', 409.0, 3.678]]`	`[['S01', 420.8, 3.784]]`	Failed
network 8	`[['S01', 157.4, 1.415]]`	`[['S01', 344.6, 3.099]]`	Failed
network 9	`[['S01', 291.5, 2.622], ['S02', 391.6, 3.522], ['S03', 553.3, 4.976]]`	`[['S01', 361.7, 3.253], ['S02', 437.0, 3.93]]`	Failed
network 12	`[['S04', 69.9, 0.628], ['S03', 332.1, 2.987], ['S00', 442.8, 3.982], ['S01', 545.9, 4.909]]`	`[['S04', 81.0, 0.728], ['S03', 376.4, 3.385]]`	Failed

SHA-256 / c6967781dfce66e4d08136d7f10423c2e1e60dd6255e13c72901c3e82851b34c

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(event, stations):
    R = 6371.0
    out = []
    for code, la, lo in stations:
        p1 = math.radians(event[0])
        p2 = math.radians(la)
        dphi = p2 - p1
        dl = math.radians(lo - event[1])
        a = math.sin(dphi / 2) ** 2 + math.cos(dphi) * math.sin(dl / 2) ** 2
        d = 2 * R * math.asin(math.sqrt(min(1.0, a)))
        if d <= 600:
            out.append([code, round(d, 1), round(math.degrees(d / R), 3)])
    return sorted(out, key=lambda r: (r[1], r[0]))
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['network 2', [[44.56, -117.35], [['S00', 33.87, -122.39], ['S01', 32.58, -119.0], ['S02', 30.34, -116.47], ['S03', 43.88, -121.21], ['S04', 32.47, -111.54]]], [['S03', 316.7, 2.848]]], ['network 3', [[37.38, -120.81], [['S00', 37.99, -119.17], ['S01', 44.87, -121.53], ['S02', 36.92, -112.06], ['S03', 45.59, -124.41], ['S04', 48.41, -124.22], ['S05', 45.33, -114.43]]], [['S00', 159.5, 1.434]]], ['network 5', [[41.23, -114.32], [['S00', 48.44, -112.36], ['S01', 39.92, -111.66], ['S02', 31.63, -118.69], ['S03', 44.86, -116.63], ['S04', 45.92, -112.0], ['S05', 31.93, -116.6]]], [['S01', 267.7, 2.408], ['S03', 445.1, 4.003], ['S04', 553.9, 4.981]]], ['network 6', [[42.93, -114.98], [['S00', 41.78, -113.99], ['S01', 46.04, -120.17], ['S02', 39.37, -111.82], ['S03', 48.06, -111.76], ['S04', 45.02, -119.59]]], [['S00', 151.6, 1.363], ['S04', 435.9, 3.92], ['S02', 476.0, 4.281], ['S01', 537.5, 4.834]]], ['network 7', [[38.24, -116.31], [['S00', 44.82, -111.25], ['S01', 41.96, -117.22], ['S02', 45.77, -122.79]]], [['S01', 420.8, 3.784]]], ['network 8', [[37.27, -120.03], [['S00', 32.27, -124.77], ['S01', 36.2, -116.4], ['S02', 46.93, -122.1], ['S03', 48.81, -114.9]]], [['S01', 344.6, 3.099]]], ['network 9', [[39.63, -120.96], [['S00', 47.23, -111.26], ['S01', 41.57, -124.4], ['S02', 43.29, -122.87], ['S03', 45.0, -116.27], ['S04', 49.12, -110.82], ['S05', 33.21, -123.87]]], [['S01', 361.7, 3.253], ['S02', 437.0, 3.93]]], ['network 12', [[39.75, -115.38], [['S00', 39.91, -122.96], ['S01', 40.0, -124.22], ['S02', 45.24, -114.12], ['S03', 36.65, -117.11], ['S04', 39.11, -115.83], ['S05', 48.17, -111.51]]], [['S04', 81.0, 0.728], ['S03', 376.4, 3.385]]]], [['network 6', [[42.93, -114.98], [['S00', 41.78, -113.99], ['S01', 46.04, -120.17], ['S02', 39.37, -111.82], ['S03', 48.06, -111.76], ['S04', 45.02, -119.59]]], [['S00', 151.6, 1.363], ['S04', 435.9, 3.92], ['S02', 476.0, 4.281], ['S01', 537.5, 4.834]]], ['network 9', [[39.63, -120.96], [['S00', 47.23, -111.26], ['S01', 41.57, -124.4], ['S02', 43.29, -122.87], ['S03', 45.0, -116.27], ['S04', 49.12, -110.82], ['S05', 33.21, -123.87]]], [['S01', 361.7, 3.253], ['S02', 437.0, 3.93]]], ['network 12', [[39.75, -115.38], [['S00', 39.91, -122.96], ['S01', 40.0, -124.22], ['S02', 45.24, -114.12], ['S03', 36.65, -117.11], ['S04', 39.11, -115.83], ['S05', 48.17, -111.51]]], [['S04', 81.0, 0.728], ['S03', 376.4, 3.385]]], ['network 14', [[36.07, -121.76], [['S00', 47.41, -116.96], ['S01', 36.95, -119.89], ['S02', 31.53, -122.92], ['S03', 32.44, -118.51], ['S04', 35.33, -113.8]]], [['S01', 193.7, 1.742], ['S03', 502.1, 4.515], ['S02', 516.1, 4.641]]], ['network 16', [[38.62, -114.83], [['S00', 44.48, -122.4], ['S01', 39.21, -110.38]]], [['S01', 390.5, 3.512]]], ['network 17', [[40.22, -115.43], [['S00', 34.58, -110.93], ['S01', 32.33, -116.94], ['S02', 42.07, -117.12]]], [['S02', 249.7, 2.245]]], ['network 18', [[36.81, -120.08], [['S00', 45.93, -122.19], ['S01', 42.64, -115.55], ['S02', 44.75, -122.18], ['S03', 41.26, -115.09], ['S04', 43.24, -121.66]]], []], ['network 20', [[44.06, -114.59], [['S00', 39.32, -110.59], ['S01', 36.71, -114.59], ['S02', 38.77, -120.99], ['S03', 31.6, -120.79]]], []]], [['network 9', [[39.63, -120.96], [['S00', 47.23, -111.26], ['S01', 41.57, -124.4], ['S02', 43.29, -122.87], ['S03', 45.0, -116.27], ['S04', 49.12, -110.82], ['S05', 33.21, -123.87]]], [['S01', 361.7, 3.253], ['S02', 437.0, 3.93]]], ['network 23', [[44.25, -117.92], [['S00', 44.39, -122.69], ['S01', 37.18, -114.68], ['S02', 44.85, -124.42], ['S03', 42.91, -119.64]]], [['S03', 203.5, 1.83], ['S00', 379.7, 3.415], ['S02', 519.2, 4.67]]], ['network 24', [[42.12, -121.58], [['S00', 39.06, -115.35], ['S01', 41.41, -121.4]]], [['S01', 80.3, 0.723]]], ['network 25', [[38.77, -114.31], [['S00', 43.94, -110.09], ['S01', 47.99, -124.55], ['S02', 48.6, -124.13], ['S03', 47.11, -121.53]]], []], ['network 26', [[42.47, -114.8], [['S00', 36.7, -111.1], ['S01', 46.83, -118.43], ['S02', 34.65, -112.02]]], [['S01', 563.3, 5.066]]], ['network 28', [[36.13, -121.64], [['S00', 30.99, -116.87], ['S01', 48.63, -114.1], ['S02', 30.53, -117.85], ['S03', 31.41, -124.62], ['S04', 35.71, -124.61]]], [['S04', 271.5, 2.442], ['S03', 592.6, 5.33]]], ['co-located station', [[40.0, -120.0], [['AAA', 40.0, -120.0], ['BBB', 41.0, -120.0]]], [['AAA', 0.0, 0.0], ['BBB', 111.2, 1.0]]], ['equal distance tie', [[0.0, 0.0], [['ZZZ', 1.0, 0.0], ['AAA', -1.0, 0.0]]], [['AAA', 111.2, 1.0], ['ZZZ', 111.2, 1.0]]]], [['network 2', [[44.56, -117.35], [['S00', 33.87, -122.39], ['S01', 32.58, -119.0], ['S02', 30.34, -116.47], ['S03', 43.88, -121.21], ['S04', 32.47, -111.54]]], [['S03', 316.7, 2.848]]], ['network 3', [[37.38, -120.81], [['S00', 37.99, -119.17], ['S01', 44.87, -121.53], ['S02', 36.92, -112.06], ['S03', 45.59, -124.41], ['S04', 48.41, -124.22], ['S05', 45.33, -114.43]]], [['S00', 159.5, 1.434]]], ['network 5', [[41.23, -114.32], [['S00', 48.44, -112.36], ['S01', 39.92, -111.66], ['S02', 31.63, -118.69], ['S03', 44.86, -116.63], ['S04', 45.92, -112.0], ['S05', 31.93, -116.6]]], [['S01', 267.7, 2.408], ['S03', 445.1, 4.003], ['S04', 553.9, 4.981]]], ['network 6', [[42.93, -114.98], [['S00', 41.78, -113.99], ['S01', 46.04, -120.17], ['S02', 39.37, -111.82], ['S03', 48.06, -111.76], ['S04', 45.02, -119.59]]], [['S00', 151.6, 1.363], ['S04', 435.9, 3.92], ['S02', 476.0, 4.281], ['S01', 537.5, 4.834]]], ['network 7', [[38.24, -116.31], [['S00', 44.82, -111.25], ['S01', 41.96, -117.22], ['S02', 45.77, -122.79]]], [['S01', 420.8, 3.784]]], ['network 8', [[37.27, -120.03], [['S00', 32.27, -124.77], ['S01', 36.2, -116.4], ['S02', 46.93, -122.1], ['S03', 48.81, -114.9]]], [['S01', 344.6, 3.099]]], ['network 9', [[39.63, -120.96], [['S00', 47.23, -111.26], ['S01', 41.57, -124.4], ['S02', 43.29, -122.87], ['S03', 45.0, -116.27], ['S04', 49.12, -110.82], ['S05', 33.21, -123.87]]], [['S01', 361.7, 3.253], ['S02', 437.0, 3.93]]], ['network 16', [[38.62, -114.83], [['S00', 44.48, -122.4], ['S01', 39.21, -110.38]]], [['S01', 390.5, 3.512]]]], [['network 8', [[37.27, -120.03], [['S00', 32.27, -124.77], ['S01', 36.2, -116.4], ['S02', 46.93, -122.1], ['S03', 48.81, -114.9]]], [['S01', 344.6, 3.099]]], ['network 12', [[39.75, -115.38], [['S00', 39.91, -122.96], ['S01', 40.0, -124.22], ['S02', 45.24, -114.12], ['S03', 36.65, -117.11], ['S04', 39.11, -115.83], ['S05', 48.17, -111.51]]], [['S04', 81.0, 0.728], ['S03', 376.4, 3.385]]], ['network 14', [[36.07, -121.76], [['S00', 47.41, -116.96], ['S01', 36.95, -119.89], ['S02', 31.53, -122.92], ['S03', 32.44, -118.51], ['S04', 35.33, -113.8]]], [['S01', 193.7, 1.742], ['S03', 502.1, 4.515], ['S02', 516.1, 4.641]]], ['network 16', [[38.62, -114.83], [['S00', 44.48, -122.4], ['S01', 39.21, -110.38]]], [['S01', 390.5, 3.512]]], ['network 17', [[40.22, -115.43], [['S00', 34.58, -110.93], ['S01', 32.33, -116.94], ['S02', 42.07, -117.12]]], [['S02', 249.7, 2.245]]], ['network 18', [[36.81, -120.08], [['S00', 45.93, -122.19], ['S01', 42.64, -115.55], ['S02', 44.75, -122.18], ['S03', 41.26, -115.09], ['S04', 43.24, -121.66]]], []], ['network 20', [[44.06, -114.59], [['S00', 39.32, -110.59], ['S01', 36.71, -114.59], ['S02', 38.77, -120.99], ['S03', 31.6, -120.79]]], []], ['network 23', [[44.25, -117.92], [['S00', 44.39, -122.69], ['S01', 37.18, -114.68], ['S02', 44.85, -124.42], ['S03', 42.91, -119.64]]], [['S03', 203.5, 1.83], ['S00', 379.7, 3.415], ['S02', 519.2, 4.67]]]]]
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 fixture	Actual	Expected	Outcome
network 2	`[['S03', 435.8, 3.919]]`	`[['S03', 316.7, 2.848]]`	Failed
network 3	`[['S00', 194.6, 1.75]]`	`[['S00', 159.5, 1.434]]`	Failed
network 5	`[['S01', 329.7, 2.965], ['S03', 478.3, 4.302], ['S04', 581.7, 5.231]]`	`[['S01', 267.7, 2.408], ['S03', 445.1, 4.003], ['S04', 553.9, 4.981]]`	Failed
network 6	`[['S00', 168.7, 1.517], ['S02', 529.2, 4.759], ['S04', 562.7, 5.061]]`	`[['S00', 151.6, 1.363], ['S04', 435.9, 3.92], ['S02', 476.0, 4.281], ['S01', 537.5, 4.834]]`	Failed
network 7	`[['S01', 425.8, 3.83]]`	`[['S01', 420.8, 3.784]]`	Failed
network 8	`[['S01', 420.8, 3.784]]`	`[['S01', 344.6, 3.099]]`	Failed
network 9	`[['S01', 439.1, 3.949], ['S02', 459.0, 4.128]]`	`[['S01', 361.7, 3.253], ['S02', 437.0, 3.93]]`	Failed
network 12	`[['S04', 87.0, 0.782], ['S03', 394.7, 3.55]]`	`[['S04', 81.0, 0.728], ['S03', 376.4, 3.385]]`	Failed

SHA-256 / a7b69b7dabae66fae11783498474977290ea25a6353a0f6047976dd64b17b0a0

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(event, stations):
    R = 6371.0
    out = []
    for code, la, lo in stations:
        p1 = math.radians(event[0])
        p2 = math.radians(la)
        dphi = p2 - p1
        dl = math.radians(lo - event[1])
        a = math.sin(dphi / 2) ** 2 + math.cos(p1) * math.cos(p2) * math.sin(dl / 2) ** 2
        d = 2 * R * math.asin(math.sqrt(min(1.0, a)))
        if d <= 600:
            out.append([code, round(d, 1), round(math.degrees(d / R), 3)])
    return sorted(out, key=lambda r: (r[1], r[0]))
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['network 2', [[44.56, -117.35], [['S00', 33.87, -122.39], ['S01', 32.58, -119.0], ['S02', 30.34, -116.47], ['S03', 43.88, -121.21], ['S04', 32.47, -111.54]]], [['S03', 316.7, 2.848]]], ['network 3', [[37.38, -120.81], [['S00', 37.99, -119.17], ['S01', 44.87, -121.53], ['S02', 36.92, -112.06], ['S03', 45.59, -124.41], ['S04', 48.41, -124.22], ['S05', 45.33, -114.43]]], [['S00', 159.5, 1.434]]], ['network 5', [[41.23, -114.32], [['S00', 48.44, -112.36], ['S01', 39.92, -111.66], ['S02', 31.63, -118.69], ['S03', 44.86, -116.63], ['S04', 45.92, -112.0], ['S05', 31.93, -116.6]]], [['S01', 267.7, 2.408], ['S03', 445.1, 4.003], ['S04', 553.9, 4.981]]], ['network 6', [[42.93, -114.98], [['S00', 41.78, -113.99], ['S01', 46.04, -120.17], ['S02', 39.37, -111.82], ['S03', 48.06, -111.76], ['S04', 45.02, -119.59]]], [['S00', 151.6, 1.363], ['S04', 435.9, 3.92], ['S02', 476.0, 4.281], ['S01', 537.5, 4.834]]], ['network 7', [[38.24, -116.31], [['S00', 44.82, -111.25], ['S01', 41.96, -117.22], ['S02', 45.77, -122.79]]], [['S01', 420.8, 3.784]]], ['network 8', [[37.27, -120.03], [['S00', 32.27, -124.77], ['S01', 36.2, -116.4], ['S02', 46.93, -122.1], ['S03', 48.81, -114.9]]], [['S01', 344.6, 3.099]]], ['network 9', [[39.63, -120.96], [['S00', 47.23, -111.26], ['S01', 41.57, -124.4], ['S02', 43.29, -122.87], ['S03', 45.0, -116.27], ['S04', 49.12, -110.82], ['S05', 33.21, -123.87]]], [['S01', 361.7, 3.253], ['S02', 437.0, 3.93]]], ['network 12', [[39.75, -115.38], [['S00', 39.91, -122.96], ['S01', 40.0, -124.22], ['S02', 45.24, -114.12], ['S03', 36.65, -117.11], ['S04', 39.11, -115.83], ['S05', 48.17, -111.51]]], [['S04', 81.0, 0.728], ['S03', 376.4, 3.385]]]], [['network 6', [[42.93, -114.98], [['S00', 41.78, -113.99], ['S01', 46.04, -120.17], ['S02', 39.37, -111.82], ['S03', 48.06, -111.76], ['S04', 45.02, -119.59]]], [['S00', 151.6, 1.363], ['S04', 435.9, 3.92], ['S02', 476.0, 4.281], ['S01', 537.5, 4.834]]], ['network 9', [[39.63, -120.96], [['S00', 47.23, -111.26], ['S01', 41.57, -124.4], ['S02', 43.29, -122.87], ['S03', 45.0, -116.27], ['S04', 49.12, -110.82], ['S05', 33.21, -123.87]]], [['S01', 361.7, 3.253], ['S02', 437.0, 3.93]]], ['network 12', [[39.75, -115.38], [['S00', 39.91, -122.96], ['S01', 40.0, -124.22], ['S02', 45.24, -114.12], ['S03', 36.65, -117.11], ['S04', 39.11, -115.83], ['S05', 48.17, -111.51]]], [['S04', 81.0, 0.728], ['S03', 376.4, 3.385]]], ['network 14', [[36.07, -121.76], [['S00', 47.41, -116.96], ['S01', 36.95, -119.89], ['S02', 31.53, -122.92], ['S03', 32.44, -118.51], ['S04', 35.33, -113.8]]], [['S01', 193.7, 1.742], ['S03', 502.1, 4.515], ['S02', 516.1, 4.641]]], ['network 16', [[38.62, -114.83], [['S00', 44.48, -122.4], ['S01', 39.21, -110.38]]], [['S01', 390.5, 3.512]]], ['network 17', [[40.22, -115.43], [['S00', 34.58, -110.93], ['S01', 32.33, -116.94], ['S02', 42.07, -117.12]]], [['S02', 249.7, 2.245]]], ['network 18', [[36.81, -120.08], [['S00', 45.93, -122.19], ['S01', 42.64, -115.55], ['S02', 44.75, -122.18], ['S03', 41.26, -115.09], ['S04', 43.24, -121.66]]], []], ['network 20', [[44.06, -114.59], [['S00', 39.32, -110.59], ['S01', 36.71, -114.59], ['S02', 38.77, -120.99], ['S03', 31.6, -120.79]]], []]], [['network 9', [[39.63, -120.96], [['S00', 47.23, -111.26], ['S01', 41.57, -124.4], ['S02', 43.29, -122.87], ['S03', 45.0, -116.27], ['S04', 49.12, -110.82], ['S05', 33.21, -123.87]]], [['S01', 361.7, 3.253], ['S02', 437.0, 3.93]]], ['network 23', [[44.25, -117.92], [['S00', 44.39, -122.69], ['S01', 37.18, -114.68], ['S02', 44.85, -124.42], ['S03', 42.91, -119.64]]], [['S03', 203.5, 1.83], ['S00', 379.7, 3.415], ['S02', 519.2, 4.67]]], ['network 24', [[42.12, -121.58], [['S00', 39.06, -115.35], ['S01', 41.41, -121.4]]], [['S01', 80.3, 0.723]]], ['network 25', [[38.77, -114.31], [['S00', 43.94, -110.09], ['S01', 47.99, -124.55], ['S02', 48.6, -124.13], ['S03', 47.11, -121.53]]], []], ['network 26', [[42.47, -114.8], [['S00', 36.7, -111.1], ['S01', 46.83, -118.43], ['S02', 34.65, -112.02]]], [['S01', 563.3, 5.066]]], ['network 28', [[36.13, -121.64], [['S00', 30.99, -116.87], ['S01', 48.63, -114.1], ['S02', 30.53, -117.85], ['S03', 31.41, -124.62], ['S04', 35.71, -124.61]]], [['S04', 271.5, 2.442], ['S03', 592.6, 5.33]]], ['co-located station', [[40.0, -120.0], [['AAA', 40.0, -120.0], ['BBB', 41.0, -120.0]]], [['AAA', 0.0, 0.0], ['BBB', 111.2, 1.0]]], ['equal distance tie', [[0.0, 0.0], [['ZZZ', 1.0, 0.0], ['AAA', -1.0, 0.0]]], [['AAA', 111.2, 1.0], ['ZZZ', 111.2, 1.0]]]], [['network 2', [[44.56, -117.35], [['S00', 33.87, -122.39], ['S01', 32.58, -119.0], ['S02', 30.34, -116.47], ['S03', 43.88, -121.21], ['S04', 32.47, -111.54]]], [['S03', 316.7, 2.848]]], ['network 3', [[37.38, -120.81], [['S00', 37.99, -119.17], ['S01', 44.87, -121.53], ['S02', 36.92, -112.06], ['S03', 45.59, -124.41], ['S04', 48.41, -124.22], ['S05', 45.33, -114.43]]], [['S00', 159.5, 1.434]]], ['network 5', [[41.23, -114.32], [['S00', 48.44, -112.36], ['S01', 39.92, -111.66], ['S02', 31.63, -118.69], ['S03', 44.86, -116.63], ['S04', 45.92, -112.0], ['S05', 31.93, -116.6]]], [['S01', 267.7, 2.408], ['S03', 445.1, 4.003], ['S04', 553.9, 4.981]]], ['network 6', [[42.93, -114.98], [['S00', 41.78, -113.99], ['S01', 46.04, -120.17], ['S02', 39.37, -111.82], ['S03', 48.06, -111.76], ['S04', 45.02, -119.59]]], [['S00', 151.6, 1.363], ['S04', 435.9, 3.92], ['S02', 476.0, 4.281], ['S01', 537.5, 4.834]]], ['network 7', [[38.24, -116.31], [['S00', 44.82, -111.25], ['S01', 41.96, -117.22], ['S02', 45.77, -122.79]]], [['S01', 420.8, 3.784]]], ['network 8', [[37.27, -120.03], [['S00', 32.27, -124.77], ['S01', 36.2, -116.4], ['S02', 46.93, -122.1], ['S03', 48.81, -114.9]]], [['S01', 344.6, 3.099]]], ['network 9', [[39.63, -120.96], [['S00', 47.23, -111.26], ['S01', 41.57, -124.4], ['S02', 43.29, -122.87], ['S03', 45.0, -116.27], ['S04', 49.12, -110.82], ['S05', 33.21, -123.87]]], [['S01', 361.7, 3.253], ['S02', 437.0, 3.93]]], ['network 16', [[38.62, -114.83], [['S00', 44.48, -122.4], ['S01', 39.21, -110.38]]], [['S01', 390.5, 3.512]]]], [['network 8', [[37.27, -120.03], [['S00', 32.27, -124.77], ['S01', 36.2, -116.4], ['S02', 46.93, -122.1], ['S03', 48.81, -114.9]]], [['S01', 344.6, 3.099]]], ['network 12', [[39.75, -115.38], [['S00', 39.91, -122.96], ['S01', 40.0, -124.22], ['S02', 45.24, -114.12], ['S03', 36.65, -117.11], ['S04', 39.11, -115.83], ['S05', 48.17, -111.51]]], [['S04', 81.0, 0.728], ['S03', 376.4, 3.385]]], ['network 14', [[36.07, -121.76], [['S00', 47.41, -116.96], ['S01', 36.95, -119.89], ['S02', 31.53, -122.92], ['S03', 32.44, -118.51], ['S04', 35.33, -113.8]]], [['S01', 193.7, 1.742], ['S03', 502.1, 4.515], ['S02', 516.1, 4.641]]], ['network 16', [[38.62, -114.83], [['S00', 44.48, -122.4], ['S01', 39.21, -110.38]]], [['S01', 390.5, 3.512]]], ['network 17', [[40.22, -115.43], [['S00', 34.58, -110.93], ['S01', 32.33, -116.94], ['S02', 42.07, -117.12]]], [['S02', 249.7, 2.245]]], ['network 18', [[36.81, -120.08], [['S00', 45.93, -122.19], ['S01', 42.64, -115.55], ['S02', 44.75, -122.18], ['S03', 41.26, -115.09], ['S04', 43.24, -121.66]]], []], ['network 20', [[44.06, -114.59], [['S00', 39.32, -110.59], ['S01', 36.71, -114.59], ['S02', 38.77, -120.99], ['S03', 31.6, -120.79]]], []], ['network 23', [[44.25, -117.92], [['S00', 44.39, -122.69], ['S01', 37.18, -114.68], ['S02', 44.85, -124.42], ['S03', 42.91, -119.64]]], [['S03', 203.5, 1.83], ['S00', 379.7, 3.415], ['S02', 519.2, 4.67]]]]]
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 fixture	Actual	Expected	Outcome
network 2	`[['S03', 316.7, 2.848]]`	`[['S03', 316.7, 2.848]]`	Passed
network 3	`[['S00', 159.5, 1.434]]`	`[['S00', 159.5, 1.434]]`	Passed
network 5	`[['S01', 267.7, 2.408], ['S03', 445.1, 4.003], ['S04', 553.9, 4.981]]`	`[['S01', 267.7, 2.408], ['S03', 445.1, 4.003], ['S04', 553.9, 4.981]]`	Passed
network 6	`[['S00', 151.6, 1.363], ['S04', 435.9, 3.92], ['S02', 476.0, 4.281], ['S01', 537.5, 4.834]]`	`[['S00', 151.6, 1.363], ['S04', 435.9, 3.92], ['S02', 476.0, 4.281], ['S01', 537.5, 4.834]]`	Passed
network 7	`[['S01', 420.8, 3.784]]`	`[['S01', 420.8, 3.784]]`	Passed
network 8	`[['S01', 344.6, 3.099]]`	`[['S01', 344.6, 3.099]]`	Passed
network 9	`[['S01', 361.7, 3.253], ['S02', 437.0, 3.93]]`	`[['S01', 361.7, 3.253], ['S02', 437.0, 3.93]]`	Passed
network 12	`[['S04', 81.0, 0.728], ['S03', 376.4, 3.385]]`	`[['S04', 81.0, 0.728], ['S03', 376.4, 3.385]]`	Passed

SHA-256 / af84679d1d589ca3f751631656c0044ce6529034edcc9ef5a192ca2745d773c3

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 2026-09-29T14:48:30.454949+00:00.

Case digest / c5b39ce8ea004a90f7f760ad7d5402b32a458e922c6d7e5d59917981cef7c9c3