GEOLOGY AND TOPO(^RAFIIY OP HAWAII. 167 



hundred feet below the highest point ^ on the rim of the erater. and that in 

 historic time the black lava floor has never been higher than it is at the present 

 time — there should be little difficnlty in following a condens(;d history of Kilauea. 

 For our purpose its history can best be related by selecting extracts from a 

 few of the best descrijjtions of conditions ;i1 the crater taken from the many 

 accounts written by eye witnesses. 



An Exploded Mountain. 



This is done with a view to liringing out two points: the ttrst that .just as 

 Mauna Loa is an excellent example of its type, Kilauea is an example of a dif- 

 ferent and rarer type, namely, a broken down or exploded volcano, that con- 

 tinues active. It is for this reason that it is spoken of as "safe" and, so far as 

 volcanoes can be, is regarded as perfectly tame, "docile," and well-behaved. 

 The second point to be developed is that of the character and periodicity of its 

 normal eruptions. 



The . explosion or explosions whicii undoubtedly brol^c Kilauea down and 

 prevented it from building up as Mauna Loa has built up. has left an un- 

 mistakable geologic record. 



Evidence of what transpired is to be found on every hand. These ex- 

 plosions, of which there apparently were several, must have been in the very 

 distant past. Their effect was to weaken and shatter the walls that surrounded 

 the crater, leaving the mountain scarred by a series of radial and concentric 

 cracks that could have been produced only by an explosion deep down within 

 the crater. As a consequence, when the molten lava rises to a certain level in 

 the erater, the pressure becomes so great on the lateral walls of the volcanic pipe 

 that the lava flood breaks through some weak spot, usually far down under- 

 neath, and the liquid lava often flows quietly out to sea through some old 

 deep-hidden conduit. 



The Rise and Faij^ of the Lu^riD Lava. 



Never since the coming of wliite man to Hawaii has there been suffi- 

 cient force to lift the liquid lava over the brink of the crater. As a result of 

 these subterranean ventings Kilauea is esteemed as the best example of a 

 "welling" crater to be found. 



The history of this volcano has 1ieen that thi'ough a period of months or 

 years'' the jiit of Halemaumau '■ tills up liUle liy little luitil it reaches the 

 maximum of height and pressure that the walls will bear. Then, owing to the 

 enormous lateral pressure exerted by the molten column of lava, the weakened 

 walls give way and the crater vents itself. The lava lake recedes to a lower 

 level, often disappearing entirely, only to fill up again in due process of time. 

 Thus in the welling and venting of Kilauea we have a sort of barometer that 

 indicates the conditions prevailing far down beneath the island. 



^ Uwekahuna. " Perhap.s nwiiig to some uiikiuiwii iiiHiu-iu-c uf the goddess Pele — who know.s ! 



' The house of everla,stiiig fli-e. 



