96 K. HONDA, T. TERADA, Y. YOSHIDA, AND D. ISITANI. 



or of Japan. As we have seen, this period nearly coincides 

 with that of the proper fundamental oscillation of the inlet 

 leading to Honolulu. 



(/) Sea waves accompanying cyclonic storms. 



Hitherto we have exclusively considered the sea waves 

 caused by the earthquake or the submarine eruption. 

 There are, however, other classes of sea waves accom- 

 panying a cyclonic storm. Tliese latter may be subdivided 

 into three kinds, that is, short and long waves and abnormal 

 rise of sea level. 



The violent short waves, the geUro as they are commonly 

 called, have usually periods of a few minutes, and are super- 

 posed by waves of still shorter periods with considerable 

 amplitudes. On the Pacific coast they cause, year after 

 year, great damages in autumn, and on the Japan Sea coast, 

 in winter. The waves are always associated with strong 

 gales ; as tliey approach a shallow shore, they increase in 

 amplitudes, and break on the shore one after another, leaving 

 damage behind them. They have probably the same origin 

 as the ordinary wind waves'"^' always observable on the surface 

 of the sea. 



Examining the records of the tide-gauges, it will be observed 

 that tliere are many cases, in which general sea-level is ab- 

 normally raised for many hours, associated with a center of 

 low pressure existing near by. For example, the record of the 

 tide-gauge in Aburatsubo (PI. LX, Fig. 1), September 28, 1902, 

 shows a remarkable upheaval of level in 7' -10'' a.m. during low 

 water, the maximum heiglit above the ordinary level being about 

 20 cm. On examining the weather chart on the same day (PI. 



*) Wheeler, Tides and Waves, Ch. X, Wind waves. 



