How to Read the Display. The seismograms displayed are from a few of the seismograph stations routinely recorded by the Northern California Seismograph Network. Each is a record of how the ground moved at a particular seismograph station in Northern California during a 24-hour period.he height of the recorded waves on the seismogram (wave amplitude) is a greatly magnified representation of the actual ground motion. A recording of an earthquake has recognizable characteristics.
View Full Profile. There are three main causes of retinal detachment, each with its own set of risk factors. The most common type is called a ârhegmatogenousâ detachment, and is caused by a tear or hole in the retina. The retina is the thin, light-sensitive tissue that lines the back inside wall of the eye.
In rare cases, a retinal detachment can occur without warning. The first signs may be: A shadow or curtain effect across part of your visual field that does not go away. Because detachments usually affect peripheral (side) vision first, you may not notice a problem until the detachment has gotten bigger. New or sudden vision loss.