February 17, 1923 Tsunami: Central Chile

On February 17, 1923 at 5 or 6:00 [local time] at Constitucion on the Maule River, strange phenomena were observed; the water level rose gradually, reaching the highest high tide mark, then fell, reaching the lowest low tide mark; the period of oscillations was 20 minutes. The amplitude of oscillations was about 2 m and continued to grow right up to 18:00, reaching a value of 3 m at that time, and then began to diminish more rapidly. The usual amplitude of high tides at Constitucion is 1 m 50 cm, and the amplitude of the highest high tides is no more than 2 m. The discharge of the Maule River in the summer is 700 m3/sec, and as a result sea water does not enter the river at high tide. The oscillations in level during the unusual phenomenon were thus on a scale greater even than the highest high tides, and since the period of these oscillations, was 20 minutes instead of 12 hours 25 minutes, they were accompanied by strong currents, whose rate at the pier, where there was usually no current at all, was 1 m/sec.

[It is possible that the date is mistaken and the description applies to the Kamchatka tsunami of Feb 4, 1923.]

(above from reference #415)

Reference #552 lists a meteorological cause.