As I know, the Earth core is solid. This is known, because it conducts also transverse waves, while liquids conduct only longitudinal waves.
But, how was it found? The inner core is in the outer core, which is liquid. Thus, it is inpermeable for the transverse waves.
So, any transverse wave originating in the crust, shouldn't be able to reach the core and vice versa.
How could it been measured?