GC: n

S: USGS – https://www.usgs.gov/faqs/what-seismic-zone-or-seismic-hazard-zone (last access: 6 June 2024); SFExaminer – https://www.sfexaminer.com/news/much-of-san-franciscos-affordable-housing-is-slated-for-seismic-hazard-zones/article_434c3984-1428-11ed-a74f-83ac2da776eb.html (last access: 6 June 2024).

N: 1.- seismic (adj): 1852, “pertaining to or of the nature of an earthquake,” from seismo- + -ic. Alternative seismal is by 1853. Related: Seismical; seismically; seismicity.

– hazard (n): c. 1300, name of a game at dice, from Old French hasard, hasart “game of chance played with dice,” also “a throw of six in dice” (12c.), of uncertain origin. Possibly from Spanish azar “an unfortunate card or throw at dice,” which is said to be from Arabic az-zahr (for al-zahr) “the die.” But this is doubtful because of the absence of zahr in classical Arabic dictionaries. Klein suggests Arabic yasara “he played at dice;” Arabic -s- regularly becomes Spanish -z-. The -d was added in French through confusion with the native suffix -ard. Sense evolved in French to “chances in gambling,” then “chances in life.” In English, sense of “chance of loss or harm, risk” first recorded 1540s.

– zone (n): late 14c., from Latin zona “geographical belt, celestial zone,” from Greek zōnē “a belt, the girdle worn by women at the hips,” from zōnnynai “to gird,” from PIE root *yos- “to gird” (source also of Avestan yasta- “girt,” Lithuanian juosiu, juosti “to gird,” Old Church Slavonic po-jasu “girdle”). The 10c. Anglo-Saxon treatise on astronomy translates Latin quinque zonas as fyf gyrdlas.

2. Although you may hear the terms “seismic zone” and “seismic hazard zone” used interchangeably, they really describe two slightly different things. A seismic zone is used to describe an area where earthquakes tend to focus; for example, the New Madrid Seismic Zone in the Central United States. A seismic hazard zone describes an area with a particular level of hazard due to earthquakes. Typically, a high seismic hazard zone is nearest a seismic zone where there are more earthquakes, and a lower seismic hazard zone is farther away from a seismic zone.

3. Another point of confusion is that the California Geological Survey has two sets of maps with the names “Earthquake Hazards Zones” and “Earthquake Fault Zones (Alquist-Priolo)”.

There was also a seismic zone system (0,1,2,3,4) used for building codes that is now obsolete. See the last question here: Earthquake Hazards 201 – Technical Q&A.

S: 1. Etymonline – https://www.etymonline.com/search?q=seismic+hazard+zone (last access: 6 June 2024). 2 to 3. USGS – https://www.usgs.gov/faqs/what-seismic-zone-or-seismic-hazard-zone (last access: 6 June 2024).

SYN: seismic zone (depending on context)

S: USGS – https://www.usgs.gov/faqs/what-seismic-zone-or-seismic-hazard-zone (last access: 6 June 2024)

CR: seism