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MEXICO CITY (Reuters) – A powerful magnitude 6.9 quake struck in the Sea of Cortez off Mexico's Baja California on Thursday, rattling buildings in tourist resorts but there were no immediate reports of damage or injuries.

"It was felt strongly, the lamp (on the ceiling) moved but there is no damage, not even broken glass," said Monserrat Gorostieta, a receptionist at a hotel in the resort of La Paz in Baja California.

Civil Defense officials in the state of Sinaloa on the east coast of the Sea of Cortez said they had no reports of damage but were investigating reports that some buildings had been evacuated.

The quake, initially reported by the U.S. Geological Survey as a magnitude 6.6, was centered in the Sea of Cortez, 65 miles south of Los Mochis in the state of Sinaloa on the mainland. It was very shallow, just 6.2 miles below the seabed.

The Pacific Tsunami center said the quake had not triggered a tsunami but could cause local waves.

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Magnitude 6.9 - GULF OF CALIFORNIA

Earthquake Details

Magnitude
6.9

Date-Time
Thursday, October 21, 2010 at 11:53:14 AM at epicenter

Location 24.843°N, 109.171°W
Depth 10 km (6.2 miles) set by location program
Region GULF OF CALIFORNIA
Distances 105 km (65 miles) S of Los Mochis, Sinaloa, Mexico
125 km (75 miles) SW of Guamuchil, Sinaloa, Mexico
140 km (85 miles) NE of La Paz, Baja California Sur, Mexico
1200 km (740 miles) WNW of MEXICO CITY, D.F., Mexico

Since yesterday............


MAP 6.9 2010/10/21 17:53:14 24.843 -109.171 10.0 GULF OF CALIFORNIA
MAP 4.6 2010/10/21 15:38:06 24.844 -109.160 26.8 GULF OF CALIFORNIA
MAP 4.2 2010/10/21 15:14:08 24.509 -109.168 10.0 GULF OF CALIFORNIA
MAP 4.7 2010/10/21 14:26:41 24.558 -109.288 26.0 GULF OF CALIFORNIA
MAP 3.8 2010/10/21 07:54:49 31.369 -116.091 3.4 BAJA CALIFORNIA, MEXICO
MAP 2.9 2010/10/21 03:02:58 31.384 -116.061 6.0 BAJA CALIFORNIA, MEXICO
MAP 3.0 2010/10/21 00:51:29 32.101 -115.241 10.0 BAJA CALIFORNIA, MEXICO
MAP 4.3 2010/10/20 23:01:54 31.358 -116.061 10.0 BAJA CALIFORNIA, MEXICO
MAP 4.0 2010/10/20 22:05:28 31.355 -116.092 10.0 BAJA CALIFORNIA, MEXICO
MAP 3.3 2010/10/20 07:42:07 32.457 -115.578 14.6 BAJA CALIFORNIA, MEXICO
MAP 4.4 2010/10/20 07:35:45 24.333 -108.950 10.1 GULF OF CALIFORNIA
MAP 5.8 2010/10/20 06:58:15 24.624 -108.993 10.0 GULF OF CALIFORNIA
MAP 4.2 2010/10/20 05:51:22 24.353 -109.110 10.7 GULF OF CALIFORNIA
MAP 4.7 2010/10/20 04:30:38 24.282 -109.266 10.0 GULF OF CALIFORNIA
MAP 5.5 2010/10/20 04:15:37 24.532 -109.104 10.0 GULF OF CALIFORNIA
MAP 4.7 2010/10/20 03:39:29 24.764 -108.864 8.1 GULF OF CALIFORNIA
MAP 2.5 2010/10/20 02:29:44 32.608 -115.771 5.4 BAJA CALIFORNIA, MEXICO

Originally Posted by noproblemo

Since yesterday............


MAP 6.9 2010/10/21 17:53:14 24.843 -109.171 10.0 GULF OF CALIFORNIA
MAP 4.6 2010/10/21 15:38:06 24.844 -109.160 26.8 GULF OF CALIFORNIA
MAP 4.2 2010/10/21 15:14:08 24.509 -109.168 10.0 GULF OF CALIFORNIA
MAP 4.7 2010/10/21 14:26:41 24.558 -109.288 26.0 GULF OF CALIFORNIA
MAP 3.8 2010/10/21 07:54:49 31.369 -116.091 3.4 BAJA CALIFORNIA, MEXICO
MAP 2.9 2010/10/21 03:02:58 31.384 -116.061 6.0 BAJA CALIFORNIA, MEXICO
MAP 3.0 2010/10/21 00:51:29 32.101 -115.241 10.0 BAJA CALIFORNIA, MEXICO
MAP 4.3 2010/10/20 23:01:54 31.358 -116.061 10.0 BAJA CALIFORNIA, MEXICO
MAP 4.0 2010/10/20 22:05:28 31.355 -116.092 10.0 BAJA CALIFORNIA, MEXICO
MAP 3.3 2010/10/20 07:42:07 32.457 -115.578 14.6 BAJA CALIFORNIA, MEXICO
MAP 4.4 2010/10/20 07:35:45 24.333 -108.950 10.1 GULF OF CALIFORNIA
MAP 5.8 2010/10/20 06:58:15 24.624 -108.993 10.0 GULF OF CALIFORNIA
MAP 4.2 2010/10/20 05:51:22 24.353 -109.110 10.7 GULF OF CALIFORNIA
MAP 4.7 2010/10/20 04:30:38 24.282 -109.266 10.0 GULF OF CALIFORNIA
MAP 5.5 2010/10/20 04:15:37 24.532 -109.104 10.0 GULF OF CALIFORNIA
MAP 4.7 2010/10/20 03:39:29 24.764 -108.864 8.1 GULF OF CALIFORNIA
MAP 2.5 2010/10/20 02:29:44 32.608 -115.771 5.4 BAJA CALIFORNIA, MEXICO

wow- we got nothing showing in Baja Norte. We must be on different plates.

Originally Posted by Woooosh

wow- we got nothing showing in Baja Norte. We must be on different plates.

This is what is over there.


Trans-Mexican Volcanic Belt
From Wikipedia, the free encyclopedia

The Trans-Mexican Volcanic Belt (Eje Volcánico Transversal) also known locally as Sierra Nevada (Snowed Mountain Range),[1] is a volcanic belt that extends 900 km from west to east across central-southern Mexico. Several of its highest peaks have snow all year long, and during clear weather, they are visible to a large proportions of those who live in Mexico on the many high plateaus from which these volcanoes rise.

From the west, it runs from Jalisco east through northern Michoacán, southern Guanajuato, southern Querétaro, México State, southern Hidalgo, the Distrito Federal, northern Morelos, Puebla and Tlaxcala, to central Veracruz. The Mexican Plateau lies to the north, bounded by the Sierra Madre Occidental to the west and Sierra Madre Oriental to the east. The Cofre de Perote and Pico de Orizaba volcanoes, in Puebla and Veracruz, mark the meeting of the Trans-Mexican Volcanic Belt with the Sierra Madre Oriental. To the south, the basin of the Balsas River lies between the Trans-Mexican Volcanic Belt and the Sierra Madre del Sur. This area is also a distinct physiographic province of the larger Sierra Madre System physiographic division.

The highest point, also the highest point in Mexico, is Pico de Orizaba (5636 m) also known as Citlaltépetl, located at 19°01′N 97°16′W / 19.017°N 97.267°W / 19.017; -97.267. This, and several of the other high peaks, are active or dormant volcanoes; other notable volcanoes in the range include (from west to east) Nevado de Colima (4339 m), Parícutin (2774 m), Nevado de Toluca (4577 m), Popocatépetl (5452 m), Iztaccíhuatl (5286 m), Matlalcueitl (4461 m) Cofre de Perote (4282 m) and Sierra Negra, a companion of the Pico de Orizaba (4580 m).

The mountains are home to the Trans-Mexican Volcanic Belt pine-oak forests, one of the Mesoamerican pine-oak forests ecoregions.

[edit] References
1.^ México, estructuras, política, económica y social
A. Gómez-Tuena, Ma.T. Orozco-Esquivel, and L. Ferrari Igneous Petrogenesis of the Trans-Mexican Volcanic Belt, Ch 5, pp. 129-182, in Susana A. Alaniz-Álvarez and Angel F. Nieto-Samaniego, eds., Geology of México, Geological Society of America Special Paper 422, 2007 ISBN 978-0813724225

With all due respect, I'm not so sure that you identified the culprit here. Given the location of the most recent quake, in the Sea of Cortez, and given the not so distant activity near Mexicali, I think what was involved here is a Southward continuation of what ultimately ties into the San Andreas fault.

What you identified has historically been the culprit with the quakes in central Mexico.

This event was farther North and West.

I could be wrong my info only comes from a geologist.

Originally Posted by noproblemo

I could be wrong my info only comes from a geologist.

Hey thanks- it was good enough for me. :) It does look like the Baja peninsula is separate, although the volcanic sites are spread out more at the north end of the chain. I guess that explains how Baja it got where it is.

Also just got this in on the plates.

http://www.platetectonics.com/book/page_5.asp shows diagrams of four types of tectonic plate movements, with possible volcanoes in two of those types. The good news is that the movement of the plates in the Bay of Cortez is of horizontal scraping, which does not normally produce volcanic action.


"Transform-Fault Boundaries: Transform-Fault Boundaries are where two plates are sliding horizontally past one another. These are also known as transform boundaries or more commonly as faults.
Most transform faults are found on the ocean floor. They commonly offset active spreading ridges, producing zig-zag plate margins, and are generally defined by shallow earthquakes. A few, however, occur on land. The San Andreas fault zone in California is a transform fault that connects the East Pacific Rise, a divergent boundary to the south, with the South Gorda -- Juan de Fuca -- Explorer Ridge, another divergent boundary to the north. The San Andreas is one of the few transform faults exposed on land. The San Andreas fault zone, which is about 1,300 km long and in places tens of kilometers wide, slices through two thirds of the length of California. Along it, the Pacific Plate has been grinding horizontally past the North American Plate for 10 million years, at an average rate of about 5 cm/yr. Land on the west side of the fault zone (on the Pacific Plate) is moving in a northwesterly direction relative to the land on the east side of the fault zone (on the North American Plate). "

Now, since the quakes in Baja have been occurring more and more frequently since last Easter, if I remember your words correctly, plus also the frequent quakes further north, my guess at this time is that the cause of the recent flurry is not volcanic but rather continued and increased horizontal shifting at the plate boundary there.

The 4.9 quake was not too far north of here in a NW direction yesterday. Bajahowodd is correct in that there has been a high concentration of seismic activity south of the border along the continuation of the San Andreas fault line.

In the linked map below the red line is the San Andreas fault. If you pan down the peninsula on the map you will see the clusters of quake activity outside Mexicali in the north and in the Sea of Cortez outside La Paz to the south, both on/near the San Andreas fault line.

But what do I know? The name may change but the fault line sure looks connected to me. I am no geologist but I would be willing to bet that what happens at one end is felt at the other in some way...

San Andreas Fault Line in Baja

It is happening up there also.

Earthquake List for Map of N America Region

It just means we are slowly on our way to the Aleutians :>)
Did'nt feel a thing up here in the sierra, but then we have had our share the last month and a half. Over 40 about 10-25 km north of us!