344 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1962 



tion of over 1 meter in height was noted on Lago Panguipulli (jBg. 2) . 

 All the smaller lakes were muddied by the movements of the waters, 

 by the landslide material carried into the lakes by the slides them- 

 selves, and by the rivers. 



The strongest shaking observed occurred on Isla Cliiloe, where, 

 over an area of 10 by 30 km., many trees, both green and dry, were 

 snapped off by the ferocity of the shaking. In some instances the 

 branches of dry trees were snapped from the trunk and fell to the 

 ground in a circle around the trees. Some trees fell to one side or the 

 other, pulling their roots from the swampy ground. 



The ground was cracked in many places in the south, usually by 

 landslides. Lurch-cracks were observed in many places near Puerto 

 Montt and on Isla Chiloe (figs. 3 and 4) . The Longitudinal Highway 

 was cracked in many places, usually by the settling of fill. Near 

 Puerto Varas a small car that was being driven along the road at 

 the time of the earthquake sank into the soft subgrade that was ex- 

 posed when the concrete surface of the road floated off to the sides. 

 This was caused by a liquefaction and subsidence of the subgrade and 

 the soil upon which the road was built (pi. 4, fig. 2). A person who 

 had been pushing a handcart was subsequently found buried in the 

 resolidified mud. 



The towns of Valdivia and Puerto Montt (figs. 2 and 3) were 

 extensively damaged by small-scale landslides and by earth flows. 

 The soil in both localities, being a fine-grained, water-soaked silty 

 clay, became liquid when subjected to the shaking of the earth. In 

 the harbor of Puerto Montt the motor ship Puyehue was caught in an 

 alluvion, a current of sand and mud that flowed from a nearby dock 

 area into the bay, thus creating for itself the unique distinction of 

 being the first sliip in history to go aground in a landslide. Unable 

 to remove the ship, but undaunted, the owners converted it into a 

 hotel. 



Application of the MM scale to this earthquake is practically im- 

 possible. The damage was done by the main shock and by a large 

 number of subsequent shocks. People became so confused that, in 

 interrogation, it was difficult to establish exactly what happened when. 

 One aspect in which the scale is not adequate concerns the effects of 

 long-period waves. The long-period movements were certainly of 

 great amplitude and produced small but persistent accelerations. 

 These were responsible for the liquefaction of the soil in many places. 

 The secondary effects, produced by landslides, soil creep, soil flow, 

 and the settling of structures into the overloaded soil, were sufficiently 

 impressive to assign MM intensity XI and possibly XII in some locali- 

 ties, where less than a kilometer away in any direction an alarmist 

 could not have assigned an MM intensity greater than VII. Figure 5 

 shows the author's best guesses as to intensity. 



