Timeline: The 1994 Northridge Earthquake

A 6.7 magnitude earthquake struck underneath the San Fernando Valley community of Northridge that hit 20 years ago Friday, killing 57 people and causing $20 billion in damage: collapsed buildings and freeway overpasses, snapped water and gas lines, rampant fires and landslides.

More: Follow @RealTime94Quake for Livetweets | Remembering the Northridge Earthquake | Quake Prep Tips

In the timeline below, follow along with the events as they unfolded:

Jan. 17, 1994:

4:31 a.m.: A major earthquake strikes in Los Angeles.

4:37 a.m.: Fires, flooding, buildings down -- widespread damage reported across Southern California.

4:39 a.m.: 5, 14, 10 freeways are severely damaged by the earthquake, the California Highway Patrol reports.

4:40 a.m.: Massive power outages are reported across LA.

4:52 a.m.: Phone service is reported down in some areas.

4:56 a.m.: A train that may have been hauling hazardous materials derails near the Chatsworth/Northridge area.

5:17 a.m.: Quake-damaged scoreboard at Anaheim Stadium crushes upper-deck seating.

5:20 a.m.: Between 30 and 40 explosions are reported on Cal State Northridge campus.

5:38 a.m.: Federal Emergency Management Agency announces it will respond to the earthquake.

5:40 a.m.: Caltech reports that the magnitude-6.6 earthquake was centered in the northern San Fernando Valley area.

5:45 a.m.: Los Angeles Mayor Richard Riordan declares a state of emergency.

6:05 a.m.: All LAX flights are canceled; Metrolink service is shut down.

6:47 a.m.: As many as 50 structures are reported on fire.

6:50 a.m.: Hundreds of gas main and water main breaks reported. Parts of LA and Ventura counties are without running water or gas.

7 a.m.: Multiple people found dead at a collapsed apartment building in the 9500 block of Reseda Blvd. in Northridge.

7:10 a.m.: All LAUSD schools are closed.

7:36 a.m.: Death caused by 14 Freeway collapse is identified as a law enforcement officer, fire spokesman says.

9:05 a.m.: Gov. Wilson declares state of emergency, asks President Bill Clinton for federal aid.

9:10 a.m.: National Guard activates its emergency operations centers to help earthquake victims

9:18 a.m.: President Bill Clinton vows to help victims deal with the earthquake and its aftermath.

10:09 a.m.: Red Cross, Salvation Army set up shelters.

10:50 a.m.: Gov. Pete Wilson tours Northridge earthquake area by helicopter.

12:02 p.m.: Power restored to nearly half of 1.4 million LADWP customers.

12:17 p.m.: Gov. Wilson dispatches 500 National Guard troops. More than 1,500 National Guard troops are expected within 24 hours.

1 p.m.: Tens of thousands of LA residents “may be homeless," Insurance Commissioner John Garamendi says.

1:10 p.m.: “Sporadic” looting leads to more than 25 arrests citywide, LAPD says.

2:08 p.m.: President Bill Clinton declares LA County a national disaster area, releasing federal relief for victims of the Northridge quake.

2:20 p.m.: Death toll rises to 29 and hundreds are injured as the search for survivors continues.

3:15 p.m. Southern California Edison reports that power is restored to all but 150,000 homes and businesses.

5:20 p.m.: At least 14 people confirmed dead at Northridge Meadows Apartments.

5:50 p.m.: City-wide curfew in LA is in effect until dawn.

Jan. 18

7:01 a.m.: Northridge Earthquake death toll rises to 33, including 15 at Northridge Meadows Apartments, officials say.

7:21 a.m.: LAUSD schools remain closed for second day and nearly all schools in surrounding districts are closed. CSU Northridge, USC and UCLA are among the colleges closed.

1:05 p.m.: Thousands of buildings in LA and Ventura counties reported damaged.

5:01 p.m.: Citywide curfew to be extended another day, LAPD Chief Willie Williams says.

7:15 p.m.: More than 800 people injured in Ventura County. Property damage estimated at more than $400 million.

7:42 p.m.: Nearly 8,000 homes are still without water in Simi Valley.

Jan. 19

6:01 a.m.: More than 500 hospitalized, 2,300 treated and released Tuesday, hospital officials say.

7:33 a.m.: LAUSD schools remain closed for third day in a row. At least 170 facilities are seriously damaged.

10:32 a.m.: President Bill Clinton arrives in Southern California.

2:36 p.m.: Los Angeles Department of Water and Power officials say three of four LA aqueducts were severed, but local water supply will last at least 7 to 10 days.

Jan. 20

7:32 a.m.: About 36,000 LADWP customers are still without water this morning for the fourth day in a row.

10:32 a.m.: Electricity restored to all parts of LA except for 7,500 customers in the San Fernando Valley, utility officials say.

11:01a.m.: Officials cancel dusk-to-dawn curfew.

2:06 p.m.: State will underwrite loans of up to $200,000 for small-business owners devastated by Northridge Earthquake, Gov. Wilson says.

Jan. 21:

7:15 a.m.: LAUSD schools remain closed for the fifth day in a row.

12:01: Death toll rises to 55 people, officials say.

Jan. 22, 1994

8:00 a.m.: LAUSD plans to reopen most schools. About 300 classrooms remain unsafe.

8:32 a.m.: Some 10,000 households in northwest San Fernando Valley remain without running water.

9:01 a.m.: Crews restore service to 40,000 homes and identify at least that many more that are still without gas, the Southern California Gas Company says.

10:05 a.m.: 236 military tents with a capacity for up to 7,340 people are expected to be in place at 7 Valley locations by nightfall.

1:00p.m. Federal government releases $283 million in earthquake aid, according to White House Press Secretary Dee Myers.