Digital spatial data for the map "Earthquakes in and near the northeastern United States, 1638-1998"

The map is an educational tool with which to inform the public about the
existence and the broad, regional nature of earthquake hazard in the Northeast.
The data were created digitally in order to ease and speed production and
publication of the map. Text on the map cautions against using the map for
scientific or engineering purposes, or to estimate hazard in small areas or at
single sites. Entries in Lineage under Data_Quality_Information explain the
reasons for this caution (see also Wheeler, 2000; reference in Lineage).

The earthquake catalog was constructed in such a way that it should not be
utilized in scientific, engineering, or hazards use (Wheeler, 2000; reference
in Lineage). Accordingly, the catalog is not being published separately, in
order to minimize the potential for misuse. It is available only as part of the
digital files from which the entire map was made.

The data are those used to make a large-format, colored map of earthquakes in
the northeastern United States and adjacent parts of Canada and the Atlantic
Ocean (Wheeler, 2000; Wheeler and others, 2001; references in
Data_Quality_Information, Lineage). The map shows the locations of 1,069 known
earthquakes of magnitude 3.0 or larger, and is designed for a non-technical
audience. Colored circles represent earthquake locations, colored and sized by
magnitude. Short descriptions, colonial-era woodcuts, newspaper headlines, and
photographs summarize the dates, times of day, damage, and other effects of
notable earthquakes. The base map shows color-coded elevation, shaded to
emphasize relief.

This metadata record describes the data on earthquakes and topography. Other
data, such as for roads and urban areas, were obtained elsewhere and we lack
metadata for them. Instead, this field cites the sources of these data that
were obtained elsewhere.