Observations of Ground Surface Deformation in Small Patches over Fault Zones: Kamchatka, 1984 through 1995

Abstract

This paper reviews high precision measurements of distances by geodimeters and elevations by first-order leveling between permanent geodetic monuments in local strain measurement patches on the coast of the Avacha Bay in order to detect strain precursors of a probable large (М > 7.0) near earthquake and to obtain quantitative characteristics of coseismic strain. We report the results of all 1984–1995 measurements in tabular form. These data are necessary for future researchers, since the extant monuments (benchmarks) can be surveyed in the future using any precision methods, to compare with the past results to derive objective inferences. No significant changes (those in excess of the double uncertainty) in elevations and distances between geodetic monuments have occurred. The large (М = 6.8) earthquake of March 2, 1992 whose epicenter was in the Avacha Bay did not give rise to any strain; no coseismic strain has been observed either. They may still have occurred, but the sensitivity of the method and the considerable distance between the strain measurement patches and the earthquake epicenter prevented detection.