Earthquake Colorado / New Mexico, USA - continuing aftershocks in the Trinidad / Raton area

Earthquake overview : After having experienced a foreshock with a magnitude of 4.6 at 5:30 PM on August 22, a second strong mainshock measuring 5.3 magnitude (5.5 initially reported)  scared the Trinidad, Raton area.
"I have Felt it" Reports --> see below + Let us know how you have felt this earthquake

UPDATE 16/09 - 16:40 UTC :
M 3.8      2011/09/16 14:51     Depth 5.0 km      NEW MEXICO / COLORADO
08:51:51 AM at epicenter
The xx th aftershock after the August 23 earthquake.
29 km (18 miles) W of Raton, New Mexico and 39 km (24 miles) SW of Trinidad, Colorado
Satellite map of the greater epicenter area

UPDATE 13/09 - 15:00 UTC :  A total of 5 aftershocks have hit the Colorado / New Mexico area
Their magnitudes, depths and epicenters :
M 2.6      2011/09/13 13:13     Depth 5.0 km      NEW MEXICO
M 2.5      2011/09/13 05:46     Depth 4.9 km      COLORADO
M 4.0      2011/09/13 05:24     Depth 5.0 km      NEW MEXICO
M 2.6      2011/09/13 02:59     Depth 9.0 km      NEW MEXICO
M 3.4      2011/09/13 01:37     Depth 6.8 km      NEW MEXICO

UPDATE 13/09 - 06:28 UTC : Aftershocks) in between Raton and Trinidad
M 4.0      2011/09/13 05:24     Depth 5.0 km      NEW MEXICO
September 12, 2011 at 11:24:39 PM at epicenter
Most powerful aftershock after the August 22 5.3 mainshock.
28 km (17 miles) W of Raton, New Mexico and 34 km (21 miles) SW of Trinidad, Colorado
Satellite map of the greater epicenter area

UPDATE 04/09 - 12:50 UTC : The aftershocks are not frequent but still happen in the greater epicenter area. These aftershocks are not powerful enough to create damage or injuries, but remind people all the time on the more powerful mainshock of August 22. Todays aftershock was 2.6 at a shallow depth of 4.8 km. 25 km (15 miles) W of Trinidad, Colorado and 41 km (25 miles) NW of Raton, New Mexico.

UPDATE 28/08 - 21:50 UTC : Aftershock measuring 2.7 at a depth of 5 km 15 km near Trinidad @ 01:25:02 PM

UPDATE : By far the best footage and even pictures of the damage were detected @ KOAA, Colorado Springs and Pueblo. Click on the picture to be linked to KOAA's website. is congratulating KOAA reporting team on their very extensive and good work.

UPDATE :  Ringo’s Super Trading Post in Segundo, Colorado has lost thousands of dollars’ worth of liquor.

UPDATE : Luckily, NO reports of injuries so far.

IMPORTANT UPDATE : Damage will exceed $100000 USD. Based on this damage ER has classified this earthquake as a minor CATDAT Orange! (damage estimate made by James Daniell, specialized damage geophysicist)

UPDATE : New aftershock list since our latest aftershock update :
M 3.9      2011/08/23 14:11     Depth 5.0 km      COLORADO
This being the strongest aftershock so far (after the mainshock). It occurred at local time : 08:11:13 AM at epicenter
22 km (13 miles) SouthWest of Trinidad, Colorado
M 2.6      2011/08/23 12:03     Depth 5.0 km      COLORADO

UPDATE : A few homes have been damaged during this earthquake. No collapsed homes, but cracks in walls, broken windows, collapsed chimneys, etc. labels this as 'minor damage'

UPDATE : Report from a girl on facebook : My father lives West of Trinidad (epicenter area ER) (Valdez-Segundo area) His chimney collapsed, walls were cracked, dishes broken. Some objects fell off the wall, but luckily everybody is safe.

UPDATE : Colorado State Patrol is reporting there is damage to I25 near mile markers 5 and 8. That is south of Trinidad, near the New Mexico state line . Las Animas County reports damage to highway 12.  They also say there is structural damage to some buildings in the area.

UPDATE : Since the mainshock the area had the usual, lesser magnitude aftershocks)
M 3.2      2011/08/23 09:37     Depth 5.0 km     COLORADO
M 3.8      2011/08/23 07:17     Depth 4.8 km     COLORADO
M 3.2      2011/08/23 07:01     Depth 5.0 km     COLORADO
M 3.5      2011/08/23 06:56     Depth 5.0 km     COLORADO
We predict that the aftershocks way go on for a while, but should normally be gradually lower in magnitude. Some exceptionally  4+ shocks are still possible.

UPDATE : This earthquake is the largest since 1973 ! The epicenter of the 1973 earthquake was located in the northwestern part of Colorado,  approx. 50 miles north of Grand Junction

UPDATE : During August and September 2001,  a number of smaller magnitude quakes were recorded in the same area than today.

UPDATE : It was also felt as a weak shaking as far as Denver, Colorado

UPDATE : The earthquake was also felt in Oklahoma and Kansas.

UPDATE : There are reports of rock-slides along a highway following the quake.

UPDATE : This earthquake follows two smaller quakes that hit the area earlier in the day:
- a magnitude 4.6 quake was recorded at 5:30 p.m. and a magnitude 2.9 quake just before 8 a.m.

UPDATE : Due to the very shallow hypocenter some damage may be possible.

"I Have Felt It" reports as received by
MMI values (if indicated) after the text (III: Weak shaking, IV Light shaking, V Moderate shaking, VI Strong shaking, VII Very Strong shaking)
Trinidad,  Colorado : The first one came at about 5:29 PM and it was not as intense as the second one. The second one was at 11:49 PM Mountain Time.  I was awake and it lasted for about 30 seconds. It woke my husband up and our neighbors about 80 acres away. It shook the whole house and a loud rumbling noise was heard. We ran outside for safety since we live near rock outcroppings we were afraid that boulders would come down on the house. Luckily apparent damage, too dark to check for structure damage now. Cabinet doors were opened and ajar, items rattled throughout the house.
?????? : It sounded like thunder only from the earth below, I noticed the wind chimes were shaking and the curtains moving, for a moment, I thought my washing machine was out of balance, but faster than I could think that I did not have clothes washing, it happened again. The noise seemed to come first , followed by the shaking. VMMI
Lakewood, Colorado : August 22, 2011, 23:49 Standard Mountain Time 693, Urban Court, Lakewood, Colorado, 11th floor. For about 3-4 sec feeling like on a ship in a mild waves IV MMI
Pueblo,  Colorado :  Shifted my bed IV MMI
Weston, Colorado : About 11:50 p.m., 8-22-11, felt the whole house shake and heard rumbling. Very scary because it was the first time I have experienced anything like it. Heard there was a earthquake earlier in the day and I did not notice that one. II-III MMI
near Boise City, OK : 12:48 a.m., Tue., 08/23/2011 Location: 1 1/2 mile south of Colorado State line, 14 miles north of Boise City, OK For about 1&1/2 to 2 seconds felt the shake while curled up on sofa, windows rattled as did curio cabinet.  Also heard low rumble.
Lamar, Colorado : The tremor at 5:30 was a weak shake,and was about 2 seconds in duration. The 11:46 tremor was light shaking, 7 to 8 seconds in duration, and was obviously an earthquake even to this inexperienced observer. Observations were made while residing in a room on the third floor of the Holiday Inn Express in Lamar, CO. II-III and IV MMI
Las Animas, Colorado : We woke up to the bed shaking and a noise like thunder. The mirror on the wall was rattling as well. We live in a very large 2-story brick house near the railroad tracks and I thought it was a big train... but no trains! It lasted about 10 seconds.  MMI VI
Alma, Illinois : I felt the Earth subtly rising and falling as I was drifting off to sleep.  I figured it was either a close quake (US) or a very large distant quake.  I waited until morning to read the reports. MMI II-III (looks far away to ER, but we give this Felt Report as we received it)
Texhoma, Oklahoma : We live in a 1920s two-story that is in good shape but moves a lot. The upstairs floors are very bouncy, and when I watch TV up there I can feel the whole house move from my reclining chair. I have built houses for over thirty years and I know how they move, new and old. I know every vibration this one makes, and this one was unfamiliar. Everyone was asleep downstairs and the doors were all locked when I went down to see what was shaking the house. It was brief, only part of a second a few seconds apart, maybe three little jolts a little greater in intensity than an outside door being closed hard would cause. I didn't think much about it at the time (the wind plays tricks here too, but I can tell the difference between wind, and people walking, and doors shutting), but the "information" in the news media this morning led me to this site because the timing lined up perfectly. (By the way, Colorado does not have any "borders". They are "state lines". New Mexico shares a border with the nation of Mexico, and state lines within one country with Arizona, Utah, Colorado, Oklahoma and Texas.) MMI IV + (Thanks for telling us about the State lines and Country borders :))
Oklahoma - live in midwest city oklahoma felt an earthquake approximately around 540pm - IV
Colorado Springs, CO - I was sitting in a chair using my computer, when the house and the chair were shaking. I have never been in an earthquake, but I knew this was one. - IV
Olathe, KS - I was at a CVS pharmacy in Olathe, KANSAS, signing in by computer for the minute clinic (for school forms for my kids).  I rested my arm against the computer desk, & the side of the desk began to move in slight waves.  I thought the desk was about to break, so I tried to wobble it on my own to see the problem.  But the desk was sturdy.  I rested my arm again, and it felt as if the side of the desk were on a boat in waves.  Knowing that a desk couldn't move like that, I announced that I felt dizzy and was about to faint.  Of course, less than a minute later, I realized I was totally fine.  When I came home from the pharmacy, I saw the news online & realized this was the precise moment of the earthquake - IV

"I Have Felt It" reports as received by EMSC
Colorado Springs
: Lasted about 10 seconds, house shook like a very strong wind, but no sound and no wind
Colorado Springs : I was frightened because I have lived in Colorado for over 5  years and have never felt an earthquake. Being from the Bay Area of California, I felt them all the time. When I felt one here in Colorado, I was like, what the heck was that? lol I didn't realize that we can have them here. Too funny.
Parker : Was sitting in chair in front of the computer, my whole chair shook! I felt it! Nothing broke or anything, was very faint but noticeable for sure!!!

Other "I Have Felt It" reports :
Pueblo, Colorado : I was awake when it hit at 11:46PM. it started and increased in intensity lasting for about 5-7 seconds, the whole house was shaking, the windows were rattling. the foundation was shaking. Nothing fell off the shelves or walls. I live in north Pueblo 86 miles north of trinidad. I too thought it was an artillery excercise at nearby Fort Carson. I gotta say I am 49 and this is a first for me. I moved from Milpitas California in 73. I thought I got away from the Danger Zone. I hope this is not a foreshock temblor.

Understanding Earthquakes in the stable Continental Region


Most of North America east of the Rocky Mountains has infrequent earthquakes. Here and there earthquakes are more numerous, for example in the New Madrid seismic zone centered on southeastern Missouri, in the Charlevoix-Kamouraska seismic zone of eastern Quebec, in New England, in the New York - Philadelphia - Wilmington urban corridor, and elsewhere. However, most of the enormous region from the Rockies to the Atlantic can go years without an earthquake large enough to be felt, and several U.S. states have never reported a damaging earthquake. The earthquakes that do occur strike anywhere at irregular intervals.
Earthquakes east of the Rocky Mountains, although less frequent than in the West, are typically felt over a much broader region. East of the Rockies, an earthquake can be felt over an area as much as ten times larger than a similar magnitude earthquake on the west coast. A magnitude 4.0 eastern U.S. earthquake typically can be felt at many places as far as 100 km (60 mi) from where it occurred, and it infrequently causes damage near its source. A magnitude 5.5 eastern U.S. earthquake usually can be felt as far as 500 km (300 mi) from where it occurred, and sometimes causes damage as far away as 40 km (25 mi).
Earthquakes everywhere occur on faults within bedrock, usually miles deep. Most of the region's bedrock was formed as several generations of mountains rose and were eroded down again over the last billion or so years.
At well-studied plate boundaries like the San Andreas fault system in California, often scientists can determine the name of the specific fault that is responsible for an earthquake. In contrast, east of the Rocky Mountains this is rarely the case. All parts of this vast region are far from the nearest plate boundaries, which, for the U.S., are to the east in the center of the Atlantic Ocean, to the south in the Caribbean Sea, and to the west in California and offshore from Washington and Oregon. The region is laced with known faults but numerous smaller or deeply buried faults remain undetected. Even most of the known faults are poorly located at earthquake depths. Accordingly, few earthquakes east of the Rockies can be linked to named faults. It is difficult to determine if a known fault is still active and could slip and cause an earthquake. In most areas east of the Rockies, the best guide to earthquake hazards is the earthquakes themselves. (Text "Understanding ..." courtesy USGS)

Most important Earthquake Data (5.3 mainshock):
Magnitude : 5.3 (initially reported as 5.5)
UTC Time : Tuesday, August 23, 2011 at 05:46:19 UTC
Local time at epicenter : Monday, August 22, 2011 at 11:46:19 PM at epicenter
Depth (Hypocenter) : 4 km (2.5 miles)
Geo-location(s) :
15 km (9 miles) WSW of Trinidad, Colorado, USA
33 km (20 miles) NW of Raton, New Mexico, USA
290 km (180 miles) S of DENVER, Colorado, USA


Links to important maps
USGS Did You Feel It Map
Google satellite map of the area showing the kind of terrain the earthquake took place
Human impact map
Historic earthquakes map
Seismic hazard map
Focal mechanism report made a short explanatory video for those among you who do just want an overview of the earthquake facts - (the title still wrongly states 5.5)

QuakeSOS+ and QuakeSOS free are iPhone applications developed by Armand Vervaeck, the founder of Earthquake Report. The Application simplifies immediate group communication to friends and family members (with your exact GPS location) and is feeding the users with Earthquake Report news. The 0.99 US$ QuakeSOS+ version will support the activities of SOS Earthquakes.

a headlines on twitter
@OnlyQuakeNews : Get all the headlines of our articles + regular updates on ongoing events
@QuakeSOS : news + automatic earthquake notifications of USGS earthquakes of M 4.0 or higher with emphasis to earthquakes in the America's and the Pacific Ocean sphere (4 and up) and a lot of the rest of the world (5 and up). This account was created for our QuakeSOS and QuakeSOS+ iPhone applications
@ShakingEarth : news + automatic earthquake notifications of EMSC earthquakes of M 4.0 or higher with emphasis to earthquakes in European and Asian / Middle East sphere (4 and up) and a lot of the rest of the world (5 and up). This account was originally created to stimulate our Facebook account
@QuakeMaps : news with mapping notifications of ALL earthquakes M 3.0 and higher from all over the world via EMSC and USGS. This account was created for our website

I did feel it – Ik heb het gevoeld – Το έκανα αισθάνεται – Yo lo siento – 我的确感到了 – 私はそれを感じていました- Ich habe es gefühlt – Bunu hissediyorum yaptı – لم أشعر أنه


  1. it was terrifying and my family and I woke up from sleeping and my mother who was in Mt. Hope hospital phoned us to make sure that everything is okay.