A choropleth map of the United States visualizes the logarithmic count of total earthquakes by state, with counties colored using a threshold-based scale from the d3.schemeOrRd sequential color scheme. The map is rendered as an SVG, with each state drawn via the d3.geoPath projection. Hovering over a state triggers a tooltip, implemented with a custom d3.tip, that displays the state name, region, and earthquake count. The geographic boundaries and earthquake data are loaded from TopoJSON and CSV files, respectively.