<!-- the random choice header images

var how_many_images = 13;
var now = new Date()
var sec = now.getSeconds()
var image = sec % how_many_images;
image +=1;
// var image = 7;

if (image==1) {
title="Array I57US at Pi&ntilde;on Flat California";
alt="Pi&ntilde;on Flat";
name="/images/arrays/pinon.jpg";
bodyTxt="Site L3 in the new infrasound array at the Pi&ntilde;on Flat Observatory in the Anza Borrego desert. The photo shows a telemetry tower and antenna, the equipment vault and the noise-reducing filter. Infrasound is subaudible sound in the atmosphere.";
width="177";
height="133";
}

if (image==2) {
title="Array I56US at the USGS Geophysical Observatory near Newport, Washington";
alt="Newport Washington";
name="/images/arrays/newport_washington_thumb.jpg";
bodyTxt="Site H1 in the new infrasound array at the Geophysical Observatory in Newport, Washington. The photo was taken after the first snow fall of the season. Shown are the vault enclosure and the GPS receiver. Also if you look closely you will see an ultrasonic wind sensor behind the vault and a lightly snow covered, above ground noise reducing filter surrounding the area";
width="177";
height="133";
}

if (image==3) {
title="Element H-3 at I56US near Newport, Washington";
alt="Newport Washington";
name="/images/arrays/H-3-circuit.jpg";
bodyTxt="The H3 element at I56US (near Newport, Washington, USA) after a particularly heavy snowfall. The 18-meter rosette filter is buried beneath the snow. The element is protected by a chain link fence topped by several strands of barb wire.";
width="177";
height="133";
}

if (image==4) {
title="H1 element at the IMS infrasound array I56US (near Newport, Washington, USA)";
alt="Newport Washington";
name="/images/arrays/I56H1.jpg";
bodyTxt="Three pods in the 18-meter rosette filter at that element can be seen as well as the armored vault, ultrasonic wind sensor, temperature sensor and GPS receiver. The element is protected by a chain link fence topped with several strands of barb wire.";
width="177";
height="133";
}

if (image==5) {
title="The H4 element at I56US (near Newport, Washington, USA) after a particularly heavy snowfall";
alt="Newport Washington";
name="/images/arrays/H-4.jpg";
bodyTxt="The 18-meter rosette filter is buried beneath the snow.  The element is protected by a chain link fence topped by several strands of barb wire";
width="177";
height="133";
}

if (image==6) {
title="Array I56US at the USGS Geophysical Observatory near Newport, Washington";
alt="Newport Washington";
name="/images/arrays/H-3.jpg";
bodyTxt="The H3 element at I56US (near Newport, Washington, USA) after a particularly heavy snowfall.  The 18-meter rosette filter is buried beneath the snow.  The element is protected by a chain link fence topped by several strands of barb wire";
width="177";
height="133";
}

if (image==7) {
title="Element 7 of the 16 element Deelen Infrasound Array (DIA)";
alt="Deelen Infrasound Array";
name="/images/arrays/deelen.jpg";
bodyTxt="Element 7 of the 16 element Deelen Infrasound Array (DIA) in the Netherlands. Porous hoses are used to reduce atmospheric noise. Laslo Evers stands near the concrete lid above the subsurface mounting of the KNMI microbarometer.";
width="177";
height="133";

}

if (image==8) {
title="I55US with Mt Erebus in the background";
alt="Deelen Infrasound Array";
name="/images/arrays/alaska.jpg";
bodyTxt="Photo by Jay Helmericks, 2002. The array is an eight element array with an outer pentagon of sensors and an inner triangle of sensors,   This configuration is very robust, its beam forming ability is better than a four element centered triangle array, even with the loss of three elements.  Its eight element performance is highly non-aliasing, and broad banded. It is located on the Ross Ice Shelf in the unique area known as Windless Bight.  Windless Bight was discovered about 100 years ago by a British Antarctic exploring party.  While not totally windless, it does have significantly less wind than most of Antarctica and is generally very quiet and a great infrasound site.";
width="177";
height="133";

}

if (image==9) {
title="IS05 at Bucklands, Tasmania, Australia";
alt="IS05 at Bucklands, Tasmania, Australia";
name="/images/arrays/IS05_H1.jpg";
bodyTxt="Element H1 of IS05 Bucklands, Tasmania, Australia. Photo by David Brown, 2003."; 
width="177";
height="133";

}

if (image==10) {
title="IS05 at Bucklands, Tasmania, Australia";
alt="IS05 at Bucklands, Tasmania, Australia";
name="/images/arrays/IS05_H2.jpg";
bodyTxt="Element H2 of IS05 Bucklands, Tasmania, Australia. Photo by David Brown, 2003."; 
width="177";
height="133";

}

if (image==11) {
title="IS05 at Bucklands, Tasmania, Australia";
alt="IS05 at Bucklands, Tasmania, Australia";
name="/images/arrays/IS05_H5.jpg";
bodyTxt="Element H5 of IS05 Bucklands, Tasmania, Australia. Photo by David Brown, 2003."; 
width="177";
height="133";

}

if (image==12) {
title="IS49 Tristan da Cunha, UK";
alt="IS49 Tristan da Cunha, UK";
name="/images/arrays/tristan.jpg";
bodyTxt="Partial view of an element array station of IS49 Tristan da Cunha, UK.\nThe construction of a five-element station at Tristan da Cunha represented an extraordinary challenge, particularly in terms of logistics. Due to the absence of a contractor to build the station, staff became directly responsible for the entire project."; 
width="177";
height="133";

}

if (image==13) {
title="IS14 Robinson Crusoe Island, Chile";
alt="IS14 Robinson Crusoe Island, Chile";
name="/images/arrays/robinson_crusoe.jpg";
bodyTxt="Station IS14 Robinson Crusoe Island, Chile. Communication system of the element H1 that is located 70 m south."; 
width="177";
height="133";

}

//-->