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Roger Weller, geology instructor
Inside the Northridge Earthquake
There as several moments within a person’s life that shape who they are as a person, for me one of those events happened on January 17, 1994 and 4:31am. The weekend was supposed to be a holiday weekend with no school on Monday because of Martin Luther King Day. There was no school Monday so I stayed up late that night, and went to bed about 4:00 am. I can remember looking out the window of my bedroom and noticing how quiet it was, I lived in a more rural community called Chatsworth a suburb of Northridge, CA. At 4:31 A.M. my mom came into my room very franticly to wake me up because there had just been a large earthquake. I remember remarking “Mom I don’t have to go to school today!” And then I felt the aftershock that shook my room and I promptly got up and got out. This was definitely a defining moment in my life as a person and shaped my future to this day.
Earthquakes occur with the movement of the earth’s tectonic plates, and when two different plates meet the plate with the greater density dives under the plate with the lesser density forming an seduction zone. The area where the two plates meet is a fault zone, as the pressure at the area grows the danger of earthquakes grows as well. When the pressure on the surrounding rocks reaches the slipping point the two plates shift and the pressure is released causing a seismic wave or an earthquake. The area under the ground where the earthquake is at is called the focus and the area directly above the focus is called the epicenter.
The Northridge earthquake occurred on Monday, January 17, 1994 at 4:31 A.M Pacific Standard Time. The earthquake was a magnitude 6.7 and lasted for 10 to 20 seconds and was felt as far away as Las Vegas, NV. The Earthquake happened at a depth of 19.0 km (11.8 mi). The Northridge earthquake casualties are officially listed as: 57 people killed and 1800 people injured. The Northridge earthquake was a surprise to the residents of the community and caused an estimated $20 Billion dollars in damage. So why was the Northridge earthquake so devastating? The earthquake struck in the San Fernando Valley about 20 Miles northwest of Los Angeles, the epicenter was located in Reseda at the intersection of Reseda Blvd and Saticoy St. The earthquake did not happen along the San Andres fault, but rather (an unknown to that point) the Northridge blind thrust fault known as the Pico Thrust Fault. A Blind Thrust Fault is when the fault plain terminates before it reaches the earth’s surface, and because of the lack of surface evidence they can go unknown until they erupt. Because of this it ended up taking several days to pin point where the Northridge earthquake actually originated at. (Wiki)
The damage to the communities of Northridge and Chatsworth were extensive. For example my school Lawrence Middle School was shut down for 2 months. From my yearbook the event was covered this way: “ The January 17, 1994 quake caused extensive damage throughout the school including parts of the MPR, Library ,Cafeteria, Classrooms, and hallways.” A large section of the main hallway at the school was destroyed by the earthquake and caused the school to build a walkway that extended into the quad so students could get to classes. As a personal note I remember running fire and earthquake drills in school in southern California. When you run these drills you never think you will ever have to use them. Damage was not just located at my school; the entire area of the San Fernando Valley was affected. Freeways were heavily damaged including Hospitals and utilities like water and power lines.
Photograph by Robert A. Eplett taken on 01-17-1