Global & Disaster Medicine

Archive for the ‘Earthquake’ Category

M 4.2 – 6km ENE of Edmond, Oklahoma

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M 6.7 – 10km SSE of Bodrum, Turkey

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M 6.4 – 98km WNW of Camana, Peru

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M 7.7 – 199km ESE of Nikol’skoye, Russia

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Earthquake: M 5.8 – 11km SSE of Lincoln, Montana


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Tectonic Summary

The July 6, 2017 M 5.8 earthquake southeast of Lincoln in western Montana occurred as the result of shallow strike slip faulting along either a right-lateral, near vertical fault trending east-southeast, or on a left-lateral vertical fault striking north-northeast. The location and focal mechanism solution of this earthquake are consistent with right-lateral faulting in association with faults of the Lewis and Clark line, a prominent zone of strike-slip, dip slip and oblique slip faulting trending east-southeast from northern Idaho to east of Helena, Montana, southeast of this earthquake. The Lewis and Clark line is a broad zone of faulting about 400 km in length, and up to 80 km wide (wider to the east). Faults within this zone, primarily of Middle Proterozoic to Holocene in age, can be traced as much as 250 km along strike, and typically change in strike from east (near Idaho) to southeast (near Helena). In the region of the July 6th earthquake, prominent faults include the St Mary’s-Helena Valley fault, and the Bald Butte fault, both right-lateral structures. More detailed field studies will be required to identify the causative fault responsible for this earthquake.

Western Montana and northwestern Wyoming have experienced at least 16 other M 5+ earthquakes within 300 km of the July 6, 2017 event over the preceding century. The largest was the August 1959 M 7.2 Hebgen Lake earthquake – the largest historic event in the intermountain region – which occurred about 280 km to the south-southeast of the July 6th event. The Hebgen Lake earthquake triggered a large landslide that resulted in significant damage and more than 28 fatalities. A M 6.9 earthquake just over 100 km to the southeast of the July 6th earthquake in June, 1925, caused significant damage, but no fatalities. A M 5.6 earthquake occurred 170 km to the south of the July 6th event in July 2005, and caused minor damage in the surrounding region.


  1. USGS National Earthquake Information Center, PDE
  2. University of Utah Seismograph Stations

Nearby Places

Direction data (below) indicate the position of the event relative to the place.

  • Lincoln, Montana
  • Helena, Montana
  • Butte, Montana
  • Missoula, Montana
  • Butte-Silver Bow (Balance), Montana


M 5.3 – 18km SE of Volcano, Hawaii

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M 5.3 – 18km SE of Volcano, Hawaii

Alaska: M 5.3 – 33km WNW of Nikiski

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California: About 7 percent of the state’s hospital buildings — 220 — are still designated as having the highest risk of collapse following an earthquake.

California Healthline

“…..These high-risk buildings must be retrofitted or rebuilt to meet certain safety standards by 2020 — the first of two deadlines….”


4/18/1906: At 5:13 a.m., an earthquake estimated at close to 8.0 on the Richter scale strikes San Francisco, California, killing thousands of people and destroying large segments of the city.

History Channel


A fault system that runs from San Diego to Los Angeles is capable of producing up to magnitude 7.4 earthquakes

Scripps :  Scripps Institution of Oceanography at the University of California San Diego.

The study, “Seismic constraints on the architecture of the Newport-Inglewood/Rose Canyon fault: Implications for the length and magnitude of future earthquake ruptures,” appears in the American Geophysical Union’s Journal of Geophysical Research.



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