HYPOELLIPSE: A computer program for determining local earthquake hypocentral parameters, magnitude, and first motion pattern
Links
- Document: Report (pdf)
- Superseding Publications:
- Download citation as: RIS | Dublin Core
Abstract
HYPOELLIPSE is a computer program for determining the hypocenters of local or near regional earthquakes and for each event the ellipsoid which encloses the one standard deviation region. Traveltimes are determined from a horizontally layered crustal structure or from a linear increase of velocity with depth. Arrival times for the first arrival of P-waves and S-waves, and S-minus P interval times can be used in the solutions. Arrival times for crustal refractions such as Pn, even at distances where they do not arrive first, can also be used. Each arrival can be weighted according to the reading clarity, epicentral distance to the station, and the deviation of its residual from the mean. The hypocenter is found using Geiger's method to minimize the root mean square (RMS) of the traveltime residuals. The magnitude of each event is calculated from the maximum amplitude and/or the signal duration. The first motions can be plotted on the printer using an equal area lower focal hemisphere projection. A map showing the location of each epicenter can be plotted directly on the printer or punched card output can be used as input to another program for plotting on a graphic plotter. The azimuth and apparent velocity of a plane wave crossing the array from a distant source can also be determined.
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | HYPOELLIPSE: A computer program for determining local earthquake hypocentral parameters, magnitude, and first motion pattern |
| Series title | Open-File Report |
| Series number | 79-431 |
| DOI | 10.3133/ofr79431 |
| Year Published | 1979 |
| Language | English |
| Publisher | U.S. Geological Survey |
| Description | iii, 57 p. |
| Google Analytic Metrics | Metrics page |