Turn off events at the start of the code and turn them back on at the end.
Option Explicit

Private Sub Workbook_SheetChange(ByVal Sh As Object, ByVal Target As Range)

    Application.ScreenUpdating = False
    Application.EnableEvents = False

    Select Case Range("F11")
        Case "1. Texas Windstorm"
            Application.Run ("macro1")
        Case "2. Louisiana Windstorm"
            Application.Run ("macro2")
        Case "3. San Francisco EQ 6.7"
            Application.Run ("macro3")
        Case "4. San Francisco EQ 8.1"
            Application.Run ("macro4")
        Case "5. California Flood"
            Application.Run ("macro5")
        Case "6. North East USA Windstorm"
            Application.Run ("macro6")
        Case "7. Los Angeles Earthquake"
            Application.Run ("macro7")
        Case "8. South Korea Windstorm"
            Application.Run ("macro8")
    End Select

    Application.EnableEvents = True
    Application.ScreenUpdating = True

End Sub
By the way, do you want this code to execute whenever any change is made in any sheet on any worksheet or only when a certain range/cell is changed?


PS Can you add code tags when posting code?