Shaken, Residents Turn to the Net
Did you feel it?
Then how do you feel about talking about it?
Seismologists studying earthquake intensity now know that Southern Californians feel good about discussing the shaking they endured in Sunday's temblor near Palm Springs.
By midafternoon Monday, nearly 27,000 people had filled out computerized questionnaires for the United States Geological Survey detailing their personal reactions to the magnitude 5.2 quake.
The 8:41 a.m. shaker was initially pegged at magnitude 5.6 but later downgraded by scientists. The epicenter was about six miles east of the desert hamlet of Anza.
Seismometers were quick to measure the quake's 8.8-mile depth and to place it on the San Jacinto fault, considered the most active in California.
But the scattered distribution of quake-measuring instruments in desert and mountain areas east of Los Angeles slowed an assessment of its intensity in areas away from the epicenter -- until the questionnaires started pouring in, that is.
By the hundreds at first and then by the thousands, those jarred out of bed or away from their Sunday breakfast tables hurried to their home computers to log on to the geological survey's earthquake website.
Along with the quake's magnitude and location, the pasadena.wr.usgs.gov/shake/ca/ website added: "Did you feel it? Tell us!"
Soon, residents' personal reports were pouring in to the geological survey's main computer in Pasadena. And it automatically began mapping where the quake was felt.
It became clear that the shaking was experienced from Ridgecrest on the north to Yuma, Ariz., on the south and from Santa Barbara on the west to Kingman, Ariz., on the east.
The interactive map showed the number of responses (three from Santa Barbara) and the intensity (III, or "weak" in Kingman) from each ZIP Code from which respondents were filing.
The intensity levels were calculated from answers to multiple-choice questions on the "Did you feel it?" survey.
The questionnaire asks if you felt it in a building and, if so, what kind of structure it was. It asks if others nearby also felt it and whether the quake was strong enough to awaken you if you were asleep.
Respondents are asked to describe how the ground shook, how many seconds it lasted and their personal reactions to it. "Was it difficult to walk?" asks one question.
