ERUPTIONS OF KILAUEA VOLCANO — RICHTER AND EATON 351 



Summit Flank 

 Eruption Eruption 



East -West component of 

 tilting of Uwekahuna 

 May 1959 to March 1960 



Tilting pattern 

 Aug IS -Oct 16 



Tilting rate I X 10 radian per month 

 063 inches per mile per month 



Tilting rate 100x10'° radians per month 

 6 34 inches per mile per month 



Figure 2. — East-west component of tilting at Uwekahuna from May 1959 to March 1960, 

 Tilting toward the west corresponds to swelling of the summit of Kilauea and tilting 

 toward the east to subsidence. Patterns of tilting around Kilauea Caldera are shown 

 for slow swelling (inset A) and for rapid subsidence (inset B). 



though these quakes were exceedingly small, their number was im- 

 pressive ; over 22,000 by November 14. Except for their smaller size 

 they closely resembled those preceding the 1955 eruption of Kilauea 

 from its east rift zone. Uncertain of the exact significance of these 

 tiny shallow quakes, remeasurement of the tilt-base changes was 

 initiated early in November. Dramatic changes had occurred: the 

 caldera region was swelling at a rate at least three times faster than 

 had been detected previously (inset A, fig. 2). 



The eruption on the night of November 14 appeared at the surface 

 with electrifying suddemiess, not in Halemaumau as anticipated, but 

 in Kilauea Iki, a pit crater about a mile long and half a mile wide, 

 separated from the summit caldera by a low, narrow ridge. Starting 

 in a single fissure halfway up the 600-foot south wall of the crater, lava 

 fountains rapidly spread laterally in both directions. By 10 p.m. 

 10 short fissures, each with 1 or more active fountains, formed a dis- 

 continuous "curtain of fire" half a mile long. Gradually activity 



