EARTH SHOWS OFF A FEW NEW MOVES

Hilltown temblors part of recent wave of seismic activity, geologists say

BOB GARDINIER STAFF WRITER
Section: Capital Region,  Page: B1

Date: Tuesday, May 19, 2009

BERNE -- Many southern Albany County residents on Monday were asking "Oh, is that what that was?"


The U.S. Geological Survey reported a magnitude 3 quake took place at 8:53 p.m. Sunday in this rural town. That was followed by a smaller quake that was recorded at 3:21 a.m. Monday.


''My wife felt it but did not know what it was until she heard it on the news,'' said Ken Weaver, who lives near the epicenter and works for the town highway department.


It surely got the attention of geologists; Sunday's temblor was the 15th small quake to shake that area since February, according to William Kelly, a geologist with the State Museum.


''We've been watching this, but we really have little idea what could be the outcome, if anything,'' Kelly said. ''We should get some experts in here to set small sensors in that area to get a better idea what is going on and if it could be leading to bigger things.''


Sunday's seismic event took place 5.6 miles underground near the intersection of county routes 1 and 3, about 10 miles southwest of Altamont, according to information from the USGS and the Lamont-Doherty Cooperative Seismographic Network.


The Monday event, which was magnitude 2.1, was at nearly the same location as Sunday's but 3.7 miles underground.


Most of the recent quakes have been under 3 on the magnitude scale and were barely felt, Kelly said.


While others in the area may not have known what was happening, Charles Ver Straeten knew it was a quake. Ver Straeten, of East Berne, is a geologist who works with Kelly.


''I heard a boom sound outside and the windows and other stuff rattled inside the house,'' Ver Straeten said.


That booming sound is not unusual if bedrock is close to the surface, as it is in Berne.


''If the area consisted of looser soils there would be no boom but there would be more ground movement,'' Ver Straeten said. ''You could compare a quake effect on the looser soil to shaking a bowl of Jell-O.''


The Hilltowns have been quaking off and on since 1977, Kelly said.


The MacGregor Fault runs from near Whitehall in Washington County south through Saratoga, where it merges with the Saratoga Fault, which runs south to Berne and the Helderbergs, Kelly said.


The quake-prone area is about 2 to 3 miles wide and runs north-south through Berne, Kelly said.


''These are all very deep earthquakes down in what we call the basement, between 3 to 9 miles below the surface,'' Kelly said.


Ver Straeten said a series of small quakes is a good thing.


''The Earth is relieving stress in small movements instead of one big quake,'' Ver Straeten said.


BOX:


Were you there?


If you felt Sunday's earthquake in Berne, the USGS wants to know at http://earthquake.usgs.gov/eqcenter/recenteqsww/.