A stacked bar chart displays earthquake counts by magnitude range (7.0+, 6–6.9, 5–5.9) for six U.S. states across the years 2017 and 2018. A dropdown menu switches between years, triggering a 750ms transition that updates bar heights, axis scales, and total labels. The visualization uses D3 v5 with `d3.stack`, `d3.scaleBand`, `d3.scaleLinear`, and ordinal color mapping, rendering SVG elements with animated transitions. Data is loaded from a CSV file via `d3.csv`.