Worth a Thousand Words

Earthquake in Costa Rica This Morning

Geologically speaking, it has been an exciting day so far here in Costa Rica. According to the USGS and OVSICORI (Observatorio Vulcanologico y Sismologico de Costa Rica) a 6.2 magnitude quake hit near the Costa Rica/Panama border, a few miles north of Puerto Armuelles, Panama, at 12:11 a.m. Location coordinates are 8.295 degrees North and 82.928 degrees West. Depth was approximately 30 miles. It lasted for over 2 minutes.

Being a geologist by profession, I checked out the seismograph reading for the 5 active volcanoes here in Costa Rica before publishing this post (which is why the post was not up earlier). Four of the five seismographs located on the volcanoes registered a quake at midnight, 11 minutes before the 6.2. Volcanoes Arenal, Rincon de la Vieja, Poas, and Irazu all had registered tremors at midnight. Volcano Turrialba did not register the earlier quake. Haven't been able to determine their magnitudes as of yet, but would make an educated guess of a high 3 or low 4. All five seismographs (Arenal, Rincon de la Vieja, Poas, Irazu, and Turrialba) all registered the 6.2 and the 4.7 that occurred around 1 a.m. Since then we have experience at least 4 more tremors: 3:38 a.m., 5 a.m., 5:53 a.m., and 7:54 a.m. (these times are approximate). These last 4 tremors, again an educated guess, were 2.5 to 4.0 in magnitude.

Someone recently asked, "How many quakes does Costa Rica have per day?" The answer is somewhere between 30 and 40 a day. Many are too light to be felt. We have somewhere between 25 to 35 large quakes per year (4.0 magnitude or above).

Blessings

...Worth a Thousand Words

A hidden stone cleft in the cloud forest of Mombacho Volcano near Granada, Nicaragua

Irazu - Part 3

This past October, our daughter, Becca, and her husband, Mike, made a trip up to Irazu with us. As usual, you back into your parking spot. This is normal practice at all the active volcanoes here in Costa Rica. It makes for a quick get-away in case of an unexpected eruption. (That pretty much includes all eruptions! LOL!) Up on Irazu that day, it was cold, windy, and shrouded in cloud-cover. Eerie and melancholy. And no other people. This is Irazu at its best, at least for me. The moisture in the air was so thick our jackets were soaked through by the time we headed back to the van. Becca and Mike took some great photos that I want to share with you.




This is the diagram (map) of the Irazu Volcano National Park as you enter the crater area.



It is dangerous around the crater rims. The edges frequently crumble off. Tremors are common and happen without warning. There are several signs like this one.



Isn't it amazing how beauty can be found in the harshest and most desolate of places!? God, our great Creator, certainly has an eye for beauty!




This crater is named Diego de la Haya, after the Spanish gentleman who made a detailed description in 1723 of the first recorded eruption. You walk past this crater on your way to the main and presently active crater.

The rims of the craters are fenced like this to discourage the overly curious, and unwise from getting to near the edge.



The rim of the principal crater. There were moments when the clouds billowed up and out of the crater and we could see the lake at the bottom. It was a greyish, milky, green that day.



A close-up shot of the flowers growing beside the fence.


The sign giving the depth and the diameter of the main crater. 300 meters = 975 feet deep. 1050 meters = 3412.5 feet in diameter.

This is our favorite photo. Even though it was windy and cold, there was a hushed quality to the place that day. It was awesome. So much power lying quiet, waiting.

IRAZU - Part 1

Volcanoes are a major part of life here in Costa Rica. They have created the rich soil that makes this little country an agricultural paradise. They are also a MAJOR tourist attraction, and Costa Rica’s economy is largely based on its ability to attract tourists.
As I mentioned in an earlier post, Irazú is definitely my favorite of Costa Rica’s five active volcanoes. From my living room window, it is one of the first thing I see every morning. Irazú’s slopes are gently rounded and covered with villages and farms. As you drive upward along the switchbacks toward the summit, the land falls away to your right in deep gorges with rushing streams and valleys with rivers below simmering like ribbons of silver in the sunlight. To your left the land slopes steeply upward and much of it is cultivated. The fields of cabbage are winding rows of green with an occasional row of purple cabbage. There are also field of carrots, broccoli, cauliflower, onions, and potatoes. In some fields, tractors move slowly as laborers stack sacks or boxes of produce into the wagon. In other fields, yokes of oxen plod along pulling carts into which the produce is stacked. As you climb higher, you often pass through veils of clouds. It is cool and hushed, the trees draped in Spanish moss and orchids. Nearing the summit, the fields of crops give way to pasture for dairy cattle. It is not uncommon to round a curve and find several very contented cows calmly standing in the middle of the road. From the summit, on a clear day, you can see the peak of another volcano, Arenal, in a range of mountains running northwest toward Nicaragua. And if you are very fortunate, and the day is very clear, you can see both oceans, the Caribbean to the east and the Pacific to the west.

Why Costa Rica Has So Many Volcanoes

Volcan Arenal - Costa Rica



Why does Costa Rica have so many volcanoes?

In the last post, I explained about tectonic plates and how they move relative to one another. Just as their movement causes earthquakes, they also cause volcanoes. Remember that there are two types of plates: continental and oceanic. The continental plate is made up of lighter materials than the oceanic plate. Costa Rica is the convergent boundary between the Caribbean and the Cocos plates. Where the collision between the two occurs, the continental plate floats up and over the oceanic plate which sinks. This causes a trench that forms a boundary. In the case of Costa Rica, this trench is off the Pacific coast and runs parallel to the coastline. This trench is called a subduction zone.

When the oceanic plate sinks beneath the leading edge of the continental plate, this is called subduction. As the two plates slide over and past one another, the oceanic materials continue to subduct or sink beneath the continental plate and as it moves inland away from the trench it gets deeper underground. Eventually it sinks deep enough to be melted into magma by the heat from the mantle. Volcanoes are the earth’s relief valves for this superheated, viscous material that is known as lava when it comes to the surface. There is a line of volcanoes through the central portion of Costa Rica where the melted oceanic materials return to the earth’s surface. This line of volcanoes extends through Costa Rica and well up into Nicaragua.

According to geologists, here in Costa Rica, there are at least 112 volcanoes. Five are considered active. They are Irazú, Poás, Turrialba, Arenal, and Rincón de la Vieja.

Volcanoes are considered to be either active, dormant, or extinct. A simple explanation will do for our purpose. Active, of course, means just that. The volcano is presently doing something. Dormant means it is inactive (asleep) and has not erupted for some time. Some scientists consider a volcano dormant if it has not erupted in the last 500 years or if it hasn’t erupted since history began to be recorded in that location. For example, the volcano may be showing no signs of activity other than the presence of hot springs in the area, but because of the hot springs it obviously is not extinct (dead). Extinct means dead. The volcano has done nothing since man has been around to observe and record, and there is no sign of any type of active.

Of the 112 volcanoes in Costa Rica, only the five mentioned above are active. The rest are either dormant or extinct. One of the dormant volcanoes is Barva which is the largest volcano in Costa Rica.

Irazú is my favorite volcano. Perhaps that is because I can see it from my living room window. It is the tallest volcano in Costa Rica and is affectionately called The Colossus. Poás, which has the second largest crater in the world, is perhaps an hour away as the crow flies, and Turrialba is about the same distance, but in the opposite direction. Rincón de la Vieja and Arenal, which has erupted everyday for the last 40 years and is considered one of the ten most active volcanoes in the world, are about an hour and a half away. Over the next few weeks, I will post about each of them and share some photos with you.
Blessings