Avalanche statistics of driven granular slides in a miniature mound

We examine avalanche statistics of rain- and vibration-driven granular slides in miniature sand mounds. A crossover from power-law to non power-law avalanche-size statistics is demonstrated as a generic driving rate ν is increased. For slowly-driven mounds, the tail of the avalanche-size distribution is a power-law with exponent -1.97 ± 0.31, reasonably close to a value previously reported for landslide volumes. The interevent occurrence times are also analyzed for slowly-driven mounds; its distribution exhibits a power-law with exponent -2.670 ± 0.001.