TEACHABLE MOMENT: Watch the videos, filmed during the shaking of two earthquakes in the Philippines, which provide two excellent visual demonstrations of the physics/engineering concept of a wave’s resonance frequency. When an earthquake’s wave(s) reach the equal an object’s resonant frequency, the object will begin to oscillate with the same period of the wave.
THE BACKGROUND: In the past 48 hours, two major earthquakes have occurred in the Philippines. A magnitude M6.1 event happened on 04/22/2019 at 21:11 hrs UTC and was 12 miles deep; the latter event was stronger with a M6.4 on 04/23/2019 at 05:37 hrs UTC and was 34 miles deep.
In the first video, found HERE, a sky-rise condominium begins to sway at the same frequency of the M6.1 earthquake surface waves, and thus, water from the rooftop’s swimming pool begins to pour over the side of the high rise building. Injuries are unknown at this time. The second video (found HERE) observes a hotel’s chandelier tiers swaying at different frequencies, dependent on the individual tier’s length, in harmony with the M6.4 earthquake’s surface wave periods. (<<< one “wave” may be comprised of several wave periods convolved together).