Pine Bluff daily graphic., 1906-04-29
but they involve ages of time.
 Earthquakes,


 Earthquakes.
 If, however. in any of these pro- ccsses there is a sudden displacement, vibrations of short duration are set up. and these, because of their sud- Gcnness, are destructive, and are Known as earthquakes It is fairly we'll established that most earthquakes arise from the sudden giving way or Slipping of strata that are being de. formed in this way by the stresses ac- ccmpanying earth movements. Usu- ally the displacement is what is known to geologists as fault Rock strata are broken by Assure, and cre wall slips past the corresponding ra,ts of the other, resulting in an es- carpment along the fault line.
 If once broken, and the stresses re- ievad, for the time being all is quiet same conditions the process is likely to be renewed with the similar re- suits. This continues until the en- crey affecting the locality is expended and once more stability is establish et. So it happens that earthquakes are frequent i'll certain regions, and they are all regions known to geolo- gists as places where mountain-form- ing processes are still active.
 Relation Earthquakes and Volcanoes.
 Sometimes earthquakes accompany volcanic activity. More often by far they occur wholly independently. The two classes of phenomena are from the nature of the procuring causes most common in similar regions. The Instability characterizine regions re gently folded into mountains is ia yorable to both types of activity both volcanic and seismic. The earths crus5 suffers folding and fault ing along those lines because they are NttthcI Liit6S. Y udliS GiC tNiIN.N E tIlGl indicate displacement of the adja- cent ends of tha broken strata of posed that such an immense move n!ent could take place at any one time. but rather that the movement vas going on for many centuries and, for the most part. almost impercepti little greater magnitude set .lp earth quake vibrations. So long as the movement continues the likelihood of earthquake recurrence remains
 New York Conditions.
 Geologic conditions about the city cf New York are fairly stable. True, the coast is slowly sinking, so that the Hudson has become but an arm Of the sea: but that is going on quiet ly and at an extremely low rate. It wholly upon the roots of an ancient mountain range, and that the rocks are folded in as complex manner as those of the Rockies; but it was all finished ages ago-so long ago that the mountains 1hemseves have been all worn down and carried particle by particle into the sea. And it is also true that the whole adjacent re- g!on has been one of volcanic activity and rather extensive faulting.
 The Palisade ridge and the noun tainous ridges back of Montclair and Paterson are igneous formations of considerable magnitude that date back to an earlier epoch. But there has been no evidence of renewal since Cretaceous time. Faulting is equally plain, and the weak zones produced thereby are in many cases followed by the present steam railways.
 Hudson Fault Line.
 The Hudson itself occupies one of these fault lines. The rock strata on opposite sides of the Hudson river at New York city do not match New Jerseys side has dropped down until the total displacement is sufficient to bring strata of Mesozcic age on level with ricks of she early Paleozoic But the escarpment produced has been worn own so that both sides now present surf'c of no great diff ference of level. This is probably the largest fault of the district, an'. v'N5' the movement was in progress. it reasonable to suppose that earth quake shocks were of frequent occur renee
 How recently this has been no one knows. The physiographc features of the region would lead one to con ciude that no movement of this sort