krdae-node-sdk

KANDİLLİ RASATHANESİ VE DEPREM ARAŞTIRMA ENSTİTÜSÜ | SDK

(KANDILLI SDK)

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Getting started

Yarn

yarn add krdae-node-sdk

NPM

npm install krdae-node-sdk --save

Example

EarthquakeService

This class is responsible for retrieving the latest earthquakes from the API and returning them as Earthquake objects.

import KRDAE_SDK from "krdae-node-sdk";

const service = new KRDAE_SDK.Earthquakes.V1();
const results: Array<Earthquake> = await service.GetLatests();
// `result` variable contains the latest 500 earthquakes.

FetchingService

This service retrieves the latest earthquake list from KRDAE and makes the data usable by performing the relevant shredding operations.

import KRDAE_SDK from "krdae-node-sdk";

const service = new KRDAE_SDK.Fetching.V1();
const results: Array<ParsedItem> = await service.GetLastEarthquakes();
// `result` variable contains the latest 500 earthquakes as a `ParsedItem` model.

const response: string = await service.GetResponse();
// The `response` value is the response body returned by KRDAE.

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Academic Knowledge

Source

Magnitudes

• TimeDependent
• Local
• SurfaceWave
• ObjectWave
• Moment

The fracture that generates an earthquake is usually deep in the earth's crust, but in large earthquakes it reaches the surface of the earth and forms surface fractures, which we call fault fractures. When an earthquake strikes, it is not possible to see the deep-seated fracture directly, so we have to estimate its surface area indirectly. In other words, although we cannot see the earthquake rupture itself, we can get an idea of its size by studying the effects it produces. As an example, suppose someone throws a stone into a pool, but we don't know the size of the stone. By listening to the sound the stone makes as it falls into the pool, or by looking at the size of the ripples in the pool, we can guess whether it is a small or a large stone. Estimating the size of an earthquake is a completely similar process. An earthquake creates ripples in the earth's crust in a similar way to the water in a pool. Devices called seismometers are used to measure the fluctuations in the earth's crust. Whichever method is used, it is essential that the center of the earthquake is accurately determined when calculating the magnitude. Returning to the example of the stone thrown into the pool, the amplitude of the waves formed on the water gradually decreases as you move away from the source point. Therefore, when interpreting the amplitude of a wave, it is essential to know how far away it is coming from. An important point to keep in mind is that the Earth's crust is never as simple as the water in a pool, but has a very complex texture with layers, folds, etc. Therefore, earthquake-induced crustal fluctuations may undergo very different changes depending on the direction of propagation. Considering these possible distortions, the results of a single seismometer are often not enough to determine the magnitude. A more reliable result is obtained by taking the average of many seismometer measurements that can monitor the earthquake from different directions and at different distances.

Time Dependent Magnitude (Md)

The principle is that a larger earthquake will cause oscillations on the seismometer for a longer period of time. How long the earthquake produces a vibration on the seismometer is measured and scaled by the distance from the epicenter. This method is used for small (M<5.0) and close (Distance<300 km) earthquakes.

Local Magnitude (Ml)

This method was first proposed by Richter in 1935 to measure earthquakes. Returning to the example of the stone thrown into the pool, this method can be likened to listening to the sound waves generated by the stone as it hits the water with a microphone placed in the water. The highest amplitude value in the sound recording will give information about the size of the stone by scaling with the distance The same principle applies when estimating the magnitude of an earthquake. This method is used for relatively small (magnitude less than 6.0) and close (less than 700 km) earthquakes. It is essential that seismometers are very well calibrated to obtain accurate values.

Surface Wave Magnitude (Ms)

This method was developed to measure large earthquakes (M>6.0) where the first two methods are inadequate. Going back to the pool example, it is based on measuring the highest amplitude of the waves that form on the surface of the water and spread from the center to the periphery in the form of rings. Such waves can propagate very long distances from the source on the earth's surface. Unlike other methods, the reliability of this method increases even more when measurements are made from a long distance.

Object Wave Magnitude (Mb)

This method is similar to the Surface Wave method, except that instead of waves propagating from the surface, waves traveling at depth are used. Returning to the pool example, the sound waves (acoustic waves) generated by the stone hitting the water can propagate long distances in the water. These sound waves can be listened to with a microphone and the highest amplitude they reach gives information about the size of the stone. The situation is similar for earthquakes. However, the earth's crust produces not only sound waves but also another type of wave called shear waves. These two types of waves are called body waves. Seismometers, unlike microphones, can record both types of waves (Body Waves).

Moment Magnitude (Mw)

This magnitude type is the most reliable compared to the others. In the scientific world, it is considered that if the moment magnitude can be calculated for an earthquake, there is no need for other magnitude types. In terms of determination, it is the most complex of all. It essentially corresponds to the construction of a mathematical model of the earthquake's occurrence. It can be calculated by a process of scientific work that can be carried out by a researcher, and therefore it is inevitable that the calculations will take a certain amount of time. It is difficult to implement automatically; it is routinely calculated in a few observatories around the world, but only for earthquakes above a certain magnitude. In practice, the Moment Magnitude can only be calculated for earthquakes above a certain magnitude (M>4.0).