Earthquake scientists use (X-ray, seismic) waves to study the characteristics of Earth's layers. Some earthquake waves cannot travel through a liquid, such as (P-waves, S-waves). Scientists believe the (outer core, inner core) must be liquid.
Seismic waves are used by earthquake scientists to study the characteristics of Earth's layers. Some earthquake waves cannot travel through a liquid, such as S-waves. This indicates that the outer core must be liquid because S-waves cannot pass through it.
