Alain Michaud's 2023 Archive

Here you find mostly the description of the earthquakes that were recorded during the year 2023.

New Year's tree, 2023 Edition

2023-12-11 Malfuction

2023-12-02 mww7.6 Mindanao, Philippines

2023-11-08 Mww7.1 Banda Sea and more

2023-11-03 Effect of local noise

2023-10-31 mww6.6 Near Coast Of Central Chile

2023-09-17 Mww5.6 Vancouver Island, Canada Region

2023-09-08 mww6.8 Morocco

2023-08-28 Mww7.1 Bali Sea

2023-07-19 mww6.5 Off Coast Of Central America

2023-07-16 mww7.2 Alaska Peninsula

2023-07-14 mww6.3 Near Coast Of Chiapas, Mexico

2023-07-10 mww6.6 North Atlantic Ocean

2023-06-18 mww6.4 Gulf Of California

2023-06-17 Instrument Drift

2023-05-25 mww6.5 Panama-Colombia Border Region

2023-05-20 mww7.1 Southeast Of Loyalty Islands

2023-05-19 mww7.7 Southeast Of Loyalty Islands

2023-05-10 mww7.6 Tonga Islands

2023-04-24 mww7.1 Kermadec Islands, New Zealand and Mww7.1 Southern Sumatra, Indonesia

2023-04-14 mww7.0 Java, Indonesia

2023-04-13 mww6.0 Vancouver Island, Canada Region

2023-02-23 Mww6.8 Tajikistan-Xinjiang Border Reg.

2023-02-06 mww7.8 Turkey.

2023-01-09 mww7.6 Tanimbar Islands Reg., Indonesia.


New Year's Tree, 2023 Edition.

The New Year's tree is both happy and sad this year. Happy because it is hyper- and super-glad to show us how colorfull it can be when we want it to be. And sad, when we look behind to those who are not with us anymore. And we see also those who are slowly forgetting their dreams.

The New Year's tree also is sad this year: next to him last year was his buddy, a gorgeous Maple Tree, fifteen inches in diameter, that we had to CUT, to allow the replacement of some pipes below. I am sure they both miss one another.

Noel2023.jpg

2023-12-11 malfunction

The feedback loop is at limit. We reposition the mass.

Activity for
        2023-12-11

2023-12-02 mww7.6 Mindanao, Philippines

COORD: 8.5266 °N, 126.4487 °E, 2023-12-02 14:37:03 UTC, 32.763 km, mww7.6, Mindanao, Philippines.

Activity for
        2023-12-02

2023-11-08 2023-11-08 Mww7.1 Banda Sea

COORD: 6.456 °S, 129.5134 °E, 2023-11-08 04:53:51 UTC, 10.0 km, Mww7.1 Banda Sea.

COORD: 6.3817 °S, 129.7785 °E, 2023-11-08 04:52:52 UTC, 10.0 km, Mwb6.7 Banda Sea.

COORD: 39.3568 °N, 48.199 °E, 2023-11-08 05:18:48 UTC, 52.562 km, mb4.8 Armenia-Azerbaijan-Iran Bord Reg.

COORD: 6.1903 °S, 129.9158 °E, 2023-11-08 05:42:39 UTC, 10.0 km, mb5.1 Banda Sea.

COORD: 6.4133 °S, 129.9523 °E, 2023-11-08 06:06:52 UTC, 10.0 km, mb5.1 Banda Sea.

COORD: 6.5339 °S, 129.5949 °E, 2023-11-08 06:57:48 UTC, 10.0 km, mb4.6 Banda Sea.

COORD: 31.622 °N, 103.982 °W, 2023-11-08 10:27:49 UTC, 7.417 km, ML(TexNet)5.2 Western Texas.

COORD: 31.613 °N, 103.994 °W, 2023-11-08 10:30:06 UTC, 7.5841 km, ML(TexNet)3.2 Western Texas.

COORD: 6.302 °S, 129.474 °E, 2023-11-08 10:43:38 UTC, 10.0 km, mb4.7 Banda Sea.

Activity for
        2023-11-08

2023-07-19 mww6.5 Off Coast Of Central America

COORD: 12.814 °N, 88.1265 °W, 2023-07-19 00:22:07 UTC, 69.727 km, mww6.5 Off Coast Of Central America.

Activity for
        2023-07-19

2023-11-03 Effect of local noise

The seismometer is in the basement of our house located in the city center. The street is right in front of the house and the distance between the seismometer and the trafic is about sixty feet. The solid rock is probably less than twenty feet below the surface. We sometimes worried if the local trafic show on our seismograms. It is possible that some of the noise is due to the to trafic and local sources, but we could never see a one-to-one correlation with a known local event. Today we can.

At 8h00 local time this morning (12h00 UTC) an excavator came right in front of the house and they removed the asphalt. They also removed the sand under the ashalt and replaced it by some new one. The excavator compacted the sand and they also brought a vibrating machine (man operated) in order to compact it even more. This operation lasted three hours until noon (14h00 UTC). At 11h00 (15h00 UTC) they were gone for lunch and the place was dead quiet until a second team came at 14h00 (16h00 UTC) to put some new asphalt. This hapened when you see the large spikes on the plot. They last until 15h00 (19h00 UTC), that's when they were gone for the week-end.

OBSERVATION: During the morning, when they were digging and compacting the sand by hitting on it "bang bang bang" using the excavator bucket and when they were vibrating the soil, we observed nothing! In the past, I have always assumed that high frequency vibrations associated to local noise are outside the passsband of the instrument this can not be seen by the instrument. But today this is an extreme case, even an excavator taping the ground in the street does ont show on the plot.

However during the afternoon, when they put the asphalt and the roller-compactor was moving on it back-and-forth, again and again, in silence, then we can see those giant spikes. I was sitting in the window and I saw the road roller, there is no doubt that its movement correspond to the spikes on the plot and it shows that the seismograph is far more sensitive to the low frequencies.

In my opinion, limiting the passband of the instrument by shutting the hig frequencies was an important factor in the design of the instrument, otherwise local noise sources could be a limiting factor.

Finally I would like to mention that the larger spikes are pointing up then the distribution function does not seem symetrical.

Activity for
        2023-11-03

2023-10-31 mww6.6 Near Coast Of Central Chile

COORD: 28.7471 °S 71.5702° W, 2023-10-31 12:33:43 UTC, 35.0 km, mww6.6, Near Coast Of Central Chile.

Activity for
        2023-10-31

2023-09-17 Mww5.6 Vancouver Island, Canada Region

COORD: 50.7956 °N, 130.2988 °W, 2023-09-17 11:28:11 UTC, 10.0 km, Mww5.6, Vancouver Island, Canada Region.

Activity for
        2023-09-17

2023-09-08 mww6.8 Morocco

COORD: 31.1095 °N, 8.4404 °W, 2023-09-08 22:11:01 UTC, 18.535 km mww6.8 Morocco.

also:

COORD: 19.4171 °N, 104.935 °W, 2023-09-08 16:37:16 UTC, 53.694 km, mww5.8, Near Coast Of Jalisco, Mexico.

also:

COORD: 19.4487 °N, 105.0212 °W, 2023-09-08 15:53:22 UTC, 35.024 km, mww5.6, Near Coast Of Jalisco, Mexico.

Activity for 2023-09-08

A powerful 6.8-magnitude earthquake struck Morocco Friday night, killing nearly 2700 people and damaging buildings in the historic city of Marrakech in what the United States Geological Survey (USGS) said was the strongest tremor to hit that part of the North African nation in more than a century.

2023-08-28 Mww7.1 Bali Sea

COORD: 6.7876 °S, 116.548 °E, 2023-08-28 19:55:31 UTC, 513.545 km, Mww7.1 Bali Sea.

Activity for
        2023-08-28

2023-07-19 mww6.5 Off Coast Of Central America

COORD: 12.814 °N, 88.1265 °W, 2023-07-19 00:22:07 UTC, 69.727 km, mww6.5 Off Coast Of Central America.

Activity for
        2023-07-19

2023-07-16 mww7.2 Alaska Peninsula

COORD: 54.4596 °N, 160.7604 °W, 2023-07-16 06:48:22 UTC, 32.571 km, mww7.2, Alaska Peninsula.

Activity for
        2023-07-16

2023-07-14 mww6.3 Near Coast Of Chiapas, Mexico

COORD: 15.0337 °N, 93.8771 °W, 2023-07-14 09:29:01 UTC, 35.0 km, mww6.3, Near Coast Of Chiapas, Mexico.

Activity for
        2023-07-14

2023-07-10 mww6.6 North Atlantic Ocean

COORD: 20.0437 °N, 61.0833 °W, 2023-07-10 20:28:25 UTC, 10.0 km, mww6.6, North Atlantic Ocean.

Activity for
        2023-07-10

2023-06-18 mww6.4 Gulf Of California

COORD: 23.2433 °N, 108.6306 °W, 2023-06-18 20:30:22 UTC, 10.0 km, mww6.4, Gulf Of California.

Activity for
        2023-06-18

2023-06-17 Instrument Drift

Instrment drift up to June 2023.

This section summarizes the instument drift for the last two an a half years. We ask the reader to closely follow the plot "Temperature [C], DC output [V] vs Time [h]" found on this page, as we give a complete description of the operation since it was put into operation. Please note that all the images in this page can be enlarged by opening them in a separate tab or window (right click on the image).

During the month of January 2021, the seismometer was operated on a table while various tests were done. Once it was found that the instrument was ready to be commissioned, it was transported to the permanent site, located 7 meters away, on the concrete floor, near the corner of the home basement. After the move the instrument zero had not significantly changed, therefore it was not necessary to reset it. As soon as the instrument was in the new position, it was turned on and the data logging was started. This event is pointed by the arrow labeled: "Start: Jan 30, 2021".

The purple line represent the temperature. The sensor is located inside the seismometer, on the frame.

The green line shows the the feedback loop filter output. This output is sometimes called "mass position" representing where the mass would go if the restoring force was removed and it was freely floating. Because it is a DC coupled signal, it is contaminated by integrator drift, metal fatigue and temperature effects, therefore its use is mainly for diagnostic purpose. Obviously this signal should never go over range. We monitor this output and we reset the mass position on the beam as required. This is easily done in-situ using the remote controlled motorized mass positioner.

Both the temperature and integrator output are sampled for a period of one minute at the end of every hour. The average is represented by one data point on the plot.

Start: Jan 30, 2021. As soon as the instrument is in position on the floor, we see the temperature going down and the drift appear.

A day or two after the "start" point we installed a thick thermal insulation jacket and a wood/Styrofoam enclosure around the instrument. Immediately after (one day) the temperature jumps up by almost two degrees. One can see on the plot the correlation between the temperature and the integrator output.

During the winter months, the temperature is more stable due to electric heating of the house. Please note that there is NO active temperature stabilization of the instrument itself or the thermal jacket or even the enclosure.

During the summer months the temperature slowly raises. The blip in April could be due to the ground around the house that unfreezes, or the house heating stops. The temperature is measured inside the instrument located on the concrete floor, while the temperature control for the room is at 1.5 meter high on the wall as well as the electric plinth.

In May, and June 2021, the data acquisition stopped on two occasions due to software bugs. However the instrument stayed ON and there was no major effect.

The July 2021 event: The instrument was left unattended for a couple of weeks. The data acquisition stopped due to a software bug. When we restarted the acquisition, we falsely believed that the instrument had gone over range, therefore we moved the mass position using the remote control. We will see that this was not the case but please observe the green dot, as the acquisition was restarted, then the new voltage value as we moved the mass to its new position.

Then we had a normal operation for two months until September 2021. Please observe a short flat section that looks like a saturation again! At this moment, the mass seemed to have reached the base-of-the-boom limit position and we had no other choice to open the instrument and shorten the spring so the mass can be re-positioned on the center of the boom. Also, the clamp that hold the spring in place was properly tightened. All these operations: opening the instrument cover, adjusting the spring, tightening the clip and closing the cover and the enclosure was done on the floor, without moving the instrument and took less than one hour. During that period, the data acquisition was NOT stopped. This September 2021 event shows an extra faster time constant glitch due to the temperature change inside the instrument. During the almost three year period covered by the plot, this was the only occasion when we had to open the instrument, or the temperature jacket/enclosure. [Update]: It appears, that this should not be necessary for another year.

In November 2021, again we believed we had to move the mass. This time we gained some confidence and we kept these settings for ten months.

At the end of August 2022 we move the mass one more time. This time it will last for four months.

At the end of December 2022 we moved the mass again. At this point, we believe that the mass is slowly reaching the base-of-the-boom limit position. One or two more mass repositioning, and we will have to open the instrument again to reset the spring length.

In conclusion, after two and a halt years of continuous operation, it seems that the slow drift is constant. Although there is a dependence with the temperature, its effect is smaller than the drift. The drift is in the same direction as if the spring or the Nylon twine holding the boom are slowly stretching.

2023-05-25 mww6.5 Panama-Colombia Border Region

COORD: 8.9283 °N, 77.0881 °W, 2023-05-25 03:05:33 UTC, 13.0 km, mww6.5, Panama-Colombia Border Region.

Activity for
        2023-05-25

2023-05-20 mww7.1 Southeast Of Loyalty Islands

COORD: 23.0622 °S, 170.4562 °E, 2023-05-20 01:51:01 UTC, 35.981 km, mww7.1, Southeast Of Loyalty Islands.

Activity for
        2023-05-20

2023-05-19 mww7.7 Southeast Of Loyalty Islands

COORD: 23.1852 °S, 170.7633 °E, 2023-05-19 02:57:03 UTC, 18.027 km, mww7.7 Southeast Of Loyalty Islands.

Activity for
        2023-05-19

2023-05-10 mww7.6 Tonga Islands

COORD: 15.6002 °S, 174.6077 °W, 2023-05-10 16:02:00 UTC, 210.097 km, mww7.6, Tonga Islands

Activity for
        2023-05-10

2023-04-24 mww7.1 Kermadec Islands, New Zealand and Mww7.1 Southern Sumatra, Indonesia

COORD: 29.9676 °S, 177.8264 °W, 2023-04-24 00:41:55 UTC, 43.063 km, mww7.1, Kermadec Islands, New Zealand.

COORD: 0.781 °S, 98.5339 °E, 2023-04-24 20:00:55 UTC, 15.462 km, Mww7.1, Southern Sumatra, Indonesia.

Activity for
        2023-04-24

2023-04-14 mww7.0 Java, Indonesia

COORD: 6.0255 °S, 112.0332 °E, 2023-04-14 09:55:45 UTC, 594.028 km, mww7.0, Java, Indonesia.

Activity for
        2023-04-14

2023-04-13 mww6.0 Vancouver Island, Canada Region

COORD: 49.2066 °N, 129.6203 °W, 2023-04-13 15:54:53 UTC, 7.275 km, mww6.0, Vancouver Island, Canada Region.

Activity for
        2023-04-13

2023-02-23 Mww6.8 Tajikistan-Xinjiang Border Reg.

COORD: 38.0726°N, 73.2077°E, 2023-02-23 00:37:40 UTC, 20.522 km, Mww6.8, Tajikistan-Xinjiang Border Reg.

Activity for
        2023-02-23

2023-02-06 mww7.8 Turkey.

I am very sorry to report the strongest earthquake that was ever recorded in Turkey and Syria. Twenty hours after the seism, the news channels are reporting a death count above 4300.

Three weeks later the death count was at 50300.

The first quake was the strongest one:

COORD: 37.1736 °N, 37.032 °E, 2023-02-06 01:17:35 UTC, 17.925 km deep, mww7.8, Turkey.

Acording to the experts, the devastation is due to the short distance to the surface (20 km).

The earthquake was immediately followed by a much smaller one, not visible on our plot:

COORD: 37.1272 °N, 36.9426 °E, 2023-02-06 01:28:15 UTC, 14.497 km deep, Mww6.7, Turkey.

As often the case, there was an echo; this time almost as strong as the original earthquake:

COORD: 38.0235 °N, 37.203 °E, 2023-02-06 10:24:49 UTC, 10.0 km deep, mww7.5, Turkey

Activity for
        2023-02-06

2023-01-09 mww7.6 Tanimbar Islands Reg., Indonesia.

COORD: 40.525°N, 124.423°W, 2022-12-20 10:34:24 UTC, 17.91 km, mw6.4 Near Coast Of Northern Calif.

Activity for
        2023-01-09