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.
1 Rhegmatogenous: as described above, this is a tear or break in the retina; it is the most common type of retinal detachment. 2  Tractional: this less common type of retinal detachment occurs when scar tissue on the retinaâs surface contracts and causes the retina to separate from the eye. Tractional: this less common type of retinal detachment occurs when scar tissue on the retinaâs surface contracts and causes the retina to separate from the eye. 2  Exudative: this is usually the result of retinal disease, inflammatory disorders, or injury to the eye.