Mohorovicic observed that earthquake waves were moving faster when recorded farther away than 200 km from where the earthquake started, known as the P waves. This characteristic is due to(1 point) Responses a change in speed because of the decreased density of the mantle. a change in speed because of the decreased density of the mantle. an increased wavelength of the seismic energy wave. an increased wavelength of the seismic energy wave. a change in speed because of the increased density of the mantle. a change in speed because of the increased density of the mantle. an error when he read the seismograph read out.