This project analyzes short-term coastal change along the Kailua shoreline on Oʻahu following a recent tsunami warning event. The objective was to assess potential shoreline movement and temporary inundation using satellite-derived water indices and visual change detection techniques.

Multitemporal Landsat Collection 2 Level-2 surface reflectance imagery was obtained from the USGS and processed within ArcGIS Pro. Pre-event and post-event scenes were selected to minimize cloud cover and tidal variation while capturing conditions immediately before and after the event.

To isolate water features, the Normalized Difference Water Index (NDWI) was calculated for each scene using the green and near-infrared bands. Quality Assessment (QA) bands were applied to mask clouds and cloud shadows, ensuring that detected changes reflected surface conditions rather than atmospheric interference. Resulting NDWI rasters were thresholded and symbolized to produce binary water extents for each time period.

A two-color change detection visualization was created by overlaying the baseline (pre-event) and post-event water extents. Areas of overlap represent no significant change, while non-overlapping regions indicate potential erosion, accretion, or temporary inundation. This approach provides an intuitive, interpretable depictions of coastal dynamics without requiring complex modeling.

The final map integrates satellite analysis with cartographic design principles, including cloud masking, transparency blending, basemap integration, and clear legend classification. This project demonstrates practical skills in remote sensing, raster analysis, and geospatial visualization, with direct application to coastal monitoring, hazard assessment, and operational geospatial support.

This analysis quantifies coastal change following storm events to support resilience planning and coastal management decisions. By comparing pre- and post-storm spatial data, the project highlights areas of erosion, accretion, and shoreline vulnerability. The results provide planners, engineers, and environmental managers with actionable insight into how storm events reshape the coastline, supporting hazard mitigation planning, infrastructure protection strategies, and long-term climate adaptation efforts.