This interactive stacked bar chart displays earthquake magnitude data across US states for selected years, with each bar broken into three magnitude-range segments. A dropdown menu switches between years, triggering smooth 750-millisecond transitions that update bar positions, axis scales, and total value labels. The visualization uses D3 v5 with SVG rendering, employing `d3.scaleBand`, `d3.scaleLinear`, `d3.scaleOrdinal`, and `d3.stack` to structure and draw the layers, while `transition().duration()` animates the state changes based on the CSV data.