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17 January 2018 · 01:08:34 UTC

Hamburg

Hamburg, Michigan, USA

  • Found by MetDetect
  • Human-verified · Marc Fries
  • Meteorites recovered
Fireball (UTC)
2018-01-17 01:08:34 ± 15 s Brown et al. 2019
Radar searched
KDTX
Meteorites
Hamburg (H4) Meteoritical Bulletin entry
MetDetect
MetDetect RUN-41 design fall · radar KDTX

Automated detection

MetDetect searched the KDTX radar around the fireball time. It found the fall: the radar cells it reports are mostly the debris identified by hand.

  • 24of the 34 hand-identified cells on KDTX found
  • 10hand-identified cells missed
  • 22cells reported that were not identified by hand
Map and height-against-time plot of the radar cells MetDetect found and the cells identified by hand
Each mark is one radar measurement cell on KDTX. Blue: found by MetDetect and identified by hand; orange squares: found only by MetDetect; green rings: identified by hand, missed by MetDetect. Left: positions (the arrow points to the radar); right: height against time after the fireball.

MetDetect RUN-41, 29 Oct 2026. Leave one fall out: every learned part was trained without the fall it is scored on. The design falls were used to develop the method, so their scores are development results; the held-out falls were not. Hand-identified cells on KDTX outside the data the search loads, not counted: 14. The hand identification is the reference these numbers are graded against.

Dark flight

After the fireball goes dark, meteorites fall freely through the wind. Each radar cell is flown down to the ground through the winds of that day; the coloured areas show where stones of each mass most likely landed, and the black line runs from light to heavy stones (solid where the radar traced it, dashed where extended).

Dark-flight map from the automatically detected radar cells
From MetDetect's cells (46 cells, KDTX). Search area for stones of 10 g and up: 12.9 km². Recovered meteorites inside it: 17 of 17.

Pixel estimate, computed by P. Shober with MetDetect: winds from ERA5 (ECMWF), masses for an ordinary-chondrite density over a range of shapes. Preliminary: it does not fit the fireball itself, so the heavy end of the line is an extrapolation. Stars mark recovered meteorites (positions checked against the published tables); they are drawn for comparison only and were never used to make the maps. Counted stones are those of 10 g and up, or of unpublished mass.

Human identification

The radar signatures of this fall were identified by hand by Marc Fries (NASA ARES, Johnson Space Center). Read the original report (archived copy).

Meteorites

Publications

Brown P. G., Vida D., Moser D. E., et al. (2019) The Hamburg meteorite fall: Fireball trajectory, orbit, and dynamics. Meteoritics & Planetary Science 54, 2027–2045

Heck P. R., Greer J., Boesenberg J. S., et al. (2020) The fall, recovery, classification, and initial characterization of the Hamburg, Michigan H4 chondrite. Meteoritics & Planetary Science 55, 2341–2359

Dyar M. D., Breitenfeld L. B., Lane M. D., et al. (2025) Spectroscopy of the Hamburg Meteorite, Michigan H4. The Planetary Science Journal 6, 240

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