Never mind, found them:
Chart1.Areas[0].ChartZoomed += MainWindow_ChartZoomed;
Chart1.Areas[0].ChartZoomedOut += MainWindow_ChartZoomedOut;
Chart1.Areas[0].ChartZoomSector += MainWindow_ChartZoomSector;
Chart1.Areas[0].ChartZoomReset += MainWindow_ChartZoomReset;