Earthquake swarms

SKY

Gold
Apr 11, 2004
9,959
269
83
M 5.3 - 31km SSE of Boca de Yuma, Dominican Republic
IV
DYFI?

Time
2019-02-04 14:33:48 (UTC)
Location
18.113°N 68.506°W
Depth
72.9 km

This must be what we are talking about. Cobra: where did you get 5.8 from?
 

cobraboy

Pro-Bono Demolition Hobbyist
Jul 24, 2004
40,966
920
113
M 5.3 - 31km SSE of Boca de Yuma, Dominican Republic
IV
DYFI?

Time
2019-02-04 14:33:48 (UTC)
Location
18.113°N 68.506°W
Depth
72.9 km

This must be what we are talking about. Cobra: where did you get 5.8 from?
On the UASD go-to official site. Then a few minutes later they changed it to 5.3.
 

Cdn_Gringo

Gold
Apr 29, 2014
7,565
433
83
It is really difficult to verify the information published by UASD. As much as I have tried, I can't pinpoint locations for all of the sensors, the details of this organization's operations are scarce and often I can't find corroborating data from an independent source.

The USGS mandate does not include earthquakes in and around the DR, yet they do document a good number of them but not necessarily all of them all the time. Quakes that are published by one source but not the other need to be viewed as potentially unverified events. The number of tremors reported by USAD seems really high most days and I can't help surmise that some of these events must be attributable to something else - USAD does not appear to have enough sensors in place in enough locations to be reporting the data that they do with a degree of confidence that I am comfortable with.

With no way to verify the data myself, I have to view most of the data for the DR with a degree of skepticism unless someone says, "hey a picture just fell off the wall. "

I am left feeling that USAD gets data from the USGS as the two sites usually document the same events, but additional USAD events are rarely reported by the USGS.
 

jimmythegreek

Bronze
Dec 4, 2008
1,066
4
0
What the director has to say is certainly historically correct in some instances, but isn't particularly useful or pragmatic as it relates to short/long term predictions going forward. The simple fact remains, that even in the presence of numerous smaller quakes (think Yellowstone awhile back, or recently NNE of Punta Cana), making any sort of prediction as to future events is the equivalent of a coin toss.

The theory that earthquake swarms are a precursor to a much larger earthquake is based on the historical record of large earthquakes that have taken place in Japan, Iran, Italy and southeast Asia that followed a series of three or more smaller quakes in the same relative area or at least along the same fault within a distance of 150 miles or so.

I personally think that lots of smaller quakes tend to reduce the likelihood of a large centralized earthquake by releasing built up tectonic stress in a given area or at least equalizing those forces over a larger portion of the fault line. It appears from the historical record that swarms more often did not lead to a major seismic event than instances where they did. Obviously there may be some factors that we do not yet understand about earthquake swarms and a greater understanding may someday give the us the ability to use the occurrence of these swarms in a more useful and accurate way.

None-the-less, if one is into flipping a coin, which much of earthquake science is still equivalent to, then it is certainly understandable that for those whose job it is to predict these events and for those who live in vulnerable areas, it may not be a good idea to completely dismiss the possibility of a much larger quake occurring in these areas of sustained activity. I may not immediately head for safe ground, but at least for a few weeks I might be more prepared to do so than I otherwise might be.

We are currently much better at predicting volcanic eruptions than we are the forceful splitting of the earth's crust.

Ramón Delanoy, director of the center, explained that "when many small events are happening in an area, sometimes a great event occurs, but this does not mean that one will necessarily happen".

https://www.diariolibre.com/actuali...ores-dentro-y-alrededor-de-la-isla-LA11997084
I lived through an earthquake swarm of about 300-400 over a period of several months in Reno, NV back in 2008...

Never resulted in a major earthquake....But shaking all the time......
 

Sailor51

Member
Oct 30, 2018
45
3
8
It is really difficult to verify the information published by UASD. As much as I have tried, I can't pinpoint locations for all of the sensors, the details of this organization's operations are scarce and often I can't find corroborating data from an independent source.

The USGS mandate does not include earthquakes in and around the DR, yet they do document a good number of them but not necessarily all of them all the time. Quakes that are published by one source but not the other need to be viewed as potentially unverified events. The number of tremors reported by USAD seems really high most days and I can't help surmise that some of these events must be attributable to something else - USAD does not appear to have enough sensors in place in enough locations to be reporting the data that they do with a degree of confidence that I am comfortable with.

With no way to verify the data myself, I have to view most of the data for the DR with a degree of skepticism unless someone says, "hey a picture just fell off the wall. "

I am left feeling that USAD gets data from the USGS as the two sites usually document the same events, but additional USAD events are rarely reported by the USGS.
Since I began planning the move to the DR I've been checking on quakes. USGS.gov gives me every quake greater than 2.5 everyday. See "latest earthquakes"
I had asked a while ago about the "small" ones and nobody seemed to notice them.
Having been in the Northridge quake in Ca. seen the destruction done to Haiti (donated a boat to move supplies to shore) it is something I pay attention to.
Good it was a horizontal shift too, otherwise the beaches ... no Tsunami.
Still planning on the move though.
 

Cdn_Gringo

Gold
Apr 29, 2014
7,565
433
83
Much less than a 3 you probably won't feel especially if it is deep much beyond 50 km and even then you almost have to be standing on top of it. My awareness threshold is 4.5+

The small shakers aren't an issue and most around these parts are 2.5 - 3.5. There are lots of them and I've stopped posting about those especially in the Mona Passage.

Come on down. As in CA you know it's a quake zone and you know these parts can produce strong quakes that can chew the place up due to building practices and poor infrastructure. We are due for another big one anytime but most days that doesn't affect the temperature of the beer.
 
May 4, 2018
97
1
18
I see some of the construction going on and wonder how bad it would be if Santo Domingo got a big quake. Earthquakes don't kill ppl, it's the buildings.

One apt I saw in Higüey had its roof made of mixes of a bag of mortar, a wheelbarrow of sand(prob unwashed beach sand) and dirt. Yes, dirt. I was tempted to steal some for my garden. Makes you wonder how much rebar they used. I don't see much real aggregate used anywhere.