Page:Popular Science Monthly Volume 69.djvu/298

294 valley, to the west of which is a high mountain which does not rise to the surface of the ocean. In the channel between the cape and the submerged mountain the earthquake rift may be supposed to run. In this channel numerous earthquake shocks have been recorded by different passing vessels. If not itself a center of disturbance, it records the line along which great disturbances have frequently passed.

The rift struck the land at the mouth of Alder Creek, above Point Arena. It crept over the hill as a deep furrow in the black, sticky adobe, veering a little to left or right according to the resistance of the soil, but always keeping in a straight line in its general direction. It may be imagined as a sort of devouring dragon, leaving its trail on the hills and destroying the works of man wherever it passes. It is hard in following its course, not to think of it as endowed with a sort of wicked life. Its movement is properly from north to south, but the opening of the great fault seems to have been really instantaneous. It took place at 5:13 and the waves lasted forty-seven seconds. It may be noted in passing that the complication of the waves at any one point was mainly due to the great length of the rift. A point immediately near the crack felt mainly the first great shock, its wave and the return wave. A point farther away felt the wave and its return jolt, followed at once by waves from farther to the north and farther to the south, these waves becoming more and more opposed to one another. The waves would then augment, neutralize, override and otherwise modify one another, the final result being the violent twisting motion, the most remarkable trait of the latter portion of the earthquake in question.

Coming over the first ridge, from the sea, the rift passed under the long bridge over Alder Creek. The land on the west side of the bridge