This database summarizes important information on paleoseismic (ancient earthquake) parameters. The data are compiled from thousands of journal articles, maps, theses, and other documents, as referenced herein. The database is designed to serve a variety of needs, both in terms of the user community and methods of delivering the data.
The descriptions contain information on geographic, geologic, and paleoseismic parameters that are deemed critical to making geologic-based assessments of seismic hazards. In addition, we provide narrative comments that clarify, justify, or expound upon these parameters. Many of the comments in the database provide justification for the paleoseismic parameters that were chosen to characterize the faults and folds.
Compilers and cooperators are listed on the web page (<http://earthquake.usgs.gov/qfaults/contrib.html>). Compilers are those who described faults or folds for the database. Cooperators are those who assisted with the development of digital fault data (traces), the database structure, or the geographical information system (GIS) interfaces.
The most recent effort began in 1990 in support of the International Lithosphere Program (ILP), which formed Working Group II-2. Its main objective was to compile a World Map of Active Faults (Vladimir Trifonov, chairman). In 1992, the USGS agreed to help compile maps and fault descriptions for countries in the Western Hemisphere (North, Central, and South America, as well as Australia and New Zealand). This work continues to date, with many of the compilations for Central and South America countries having been published.
In 1993, the U.S. Geological Survey began developing a database for Quaternary faults and folds for the United States in earnest, largely supported by NEHRP but with significant support from many State surveys. This product is more robust than the ILP products, mainly owing to the vast amount of data that has become available within the U.S. in the past 20-30 years and the importance that this data plays in regional and national seismic-hazard assessments (Petersen and others, 1996; Frankel and others, 1996).
For this compilation, we have limited our compilation to synthesis of published literature relevant to the United States. Our definition of published literature includes typical sources (journals and maps), as well as M.S. theses and Ph.D. dissertations, governmental contract reports (which includes many NEHRP-sponsored studies), abstracts, and open-file (preliminary) reports. We generally do not cite unpublished field mapping, field notes, and other gray-literature reports that are not generally available to the public. The data presented in the compilation are extensively referenced using the standard USGS reference style, with the exception of attaching a unique number to each cited reference for convenience. This numeric identifier allows us to clearly cite multiple-same year publications for authors.
For a complete list of contributors, see <http://earthquake.usgs.gov/qfaults/contrib.html>
>First digit: fault visibility code
>1 = exposed
>2 =
concealed
>3 = inferred
>
>Second digit: fault age
code
>1 = historic
>2 = Holocene < 15,000 years
>3
= late Quaternary < 130,000 years
>4 = mid to late Quaternary
< 750,000 years
>5 = Quaternary < 1,600,000 years
>6 =
class B
>7 = unknown
>0 = unknown
>
>Third
digit: fault slip rate code
>1 = >5 mm/year
>2 =
1-5
>3 = .2 - 1
>4 = < .2 mm/year