Field survey of the 1992 Nicaragua tsunami

Abstract

An earthquake occurred off the west coast of Nicaragua at 18 h 16 m on September 1, 1992. Despite a relatively modest magnitude (M_s = 7.0 M_w = 7.6), the earthquake generated a significant tsunami, which strongly impacted the coast of Nicaragua and was felt at several remote stations. In an attempt to better understand the tsunami propagation and coastal impact, we conducted a field survey on November 2–7, 1992, i.e., roughly 2 months after the event. We emphasized the observation of run‐up and inundation, but also collected a limited number of sand samples and mud cores. A total of 12 sites were surveyed, with multiple stations per site. This article presents the results of the survey, including a detailed discussion of the observation methods and data processing strategies. Observed run‐ups (relative to MSL) were typically in the 4–7 m range, with a maximum run‐up of 9.1 m at San Martin, an open coast site with a steep beach slope. Inundation extents were relatively modest, typically of the order of a few hundred meters.

Keywords:

• tsunami
• Nicaragua
• field observations
• long waves
• run‐up