Скачать или смотреть Receiver function wavefield animations in the contiguous United States.

Using seismic stations deployed by EarthScope program and existing seismic records, we are able to image the subsurface structure beneath the contiguous United States with an unprecedented resolution. This animation uses one type of geophysical observations, receiver function, that can be used to decipher structural variations beneath our feet. Thanks to the dense station coverage, we have developed a new way to process receiver functions, receiver function smoothing, that have helped improve images of the subsurface. In this animation, we compare the traditional (single-station averaged) receiver functions with the spatially smoothed receiver functions.

In the animation, each circle in the maps represents a seismic station at which we have computed a single-station averaged receiver function. The color shows the amplitude of (top left) the receiver function averaged at each station or (top right) the spatially smoothed receiver function. The waveform plots (lower panels) show the average of all receiver functions, and the red lines indicate the time of the maps on the waveforms. The seismic phase around 5 s is the converted phase from the crust-mantle transition. The signals around 14 s and 23 s are multiples from the crust-mantle transition. Around 45 s, the maps show seismic signals from the 410-km discontinuity. The signal around 70 s is from the 660-km discontinuity.

Chengping Chai
Pennsylvania State University