Techniques for performing an acoustic rheology measurement of a sample are provided. A first set of acoustic pulses is provided by a focused ultrasound transducer to induce surface oscillations of the sample. A second set of acoustic pulses is provided by a detection transducer to interrogate the sample and detect the echo pulses reflected by the sample surface as a function of time. The detection ultrasound transducer system converts the echo signals to an electrical signal associated with the detected echo pulses, and a processor determines a dynamic displacement of the interface of the sample as a function of time. The processor also determines the spectrum, resonant surface oscillation frequency, and damping coefficient. Viscoelastic properties of the material are determined from these measurements, with applications for the characterization of the blood clotting process, the identification of a blood clot, gelation process, tumor, or fibrosis based on the viscoelastic properties.