COSTA RICA— VULCAN'S SMITHY 



499 



THE BOTTOM OF POAS CRATER 



Photo by J. Fid Tristan 



ends near the southwestern extremity of 

 Lake Nicaragua with Mount Orosi, the 

 conical form of which denotes its igne- 

 ous origin. But between it and the Poas 

 geyser there are a number of other cra- 

 ters, some still in semi-active condition 

 and the others quite extinct. Among the 

 latter, the most conspicuous are Tenorio 

 and Miravalles, well known to the offi- 

 cers of coasting vessels trading between 

 Panama and San Francisco, because they 

 are the beacons which indicate the posi- 

 tion of the Gulf of Nicoya and the port 

 of Puntarenas. We must not forget to 

 add that the altitude of the range de- 

 creases steadily from Irazu westward, 

 the peak of Orosi having an altitude of 

 only 5,154 feet. 



ROCKED BY EARTHQUAKES 



The maximum of volcanic activity 

 takes place at the eastern end of the 



range, and it is also that section of the 

 country, just at its southern foot, between 

 Turrialba and Poas — the so-called cen- 

 tral plateau — that is most exposed to 

 disastrous earthquakes. It is at the same 

 time the most densely populated part of 

 the whole country. 



This central plateau then is almost 

 constantly rocked by underground con- 

 vulsions of variable intensity. From 

 1866 to 1903, inclusive, the average 

 yearly number of recorded shocks was 

 34, about half of which were generally 

 felt in San Jose and its immediate vicin- 

 ity. The maximum number of shocks. 

 103, was reached in 1900, but during that 

 year there were no very heav}- quakes. 

 Contrary to the opinion current among 

 the natives, that these earthquake phe- 

 nomena are more frequent at the begin- 

 ning and at the end of the rainy season — 

 a view formerlv sustained bv the writer 



