Atleast $$3$$ seismograph stations are used to locate the epicentre of an earthquake. We find the distance from each seismograph station to the earthquake epicenter. The interception of the three circles is the epicenter (shown as a red dot in the figure.)

The Richter magnitude scale was developed in 1935 by Charles F. Richter of the California Institute of Technology as a mathematical device to compare the size of earthquakes.
A Richter scale is normally numbered 1-10, though there is no upper limit. Earthquakes measuring 1-2 on the scale happen regularly, and they are so small that people cannot feel them. Earthquakes measuring upwards of 7 are less frequent but very powerful and can cause a lot of destruction.

A seismograph is a device that measures and records the seismic waves moving through the earth post an earthquake.

The tremors produce waves on the surface of the earth. These are called seismic waves.

Carrying umbrella is not a good idea at all during thunderstorms.
As a lightning flash travels toward the ground from a nearby cloud, it looks for the tallest object. This is because all the objects attached to the ground acts as ground or earthed objects. So lightning takes the shortest path to travel and thus, falls on the tallest object. If you're holding an umbrella in an area surrounded by taller buildings, it's not so risky. But If you are the only tall object in the place surrounding you, the lightning flash will fall on you. 
Thus, carrying umbrella is not a good idea at all during thunderstorms.

A seismograph is a device that is used to record and measure the magnitude of seismic waves created by earthquakes.

When refill is rubbed on polythene it acquires small electric charges. Due to presence of these charges, pieces of paper gets attracted.

Seismograph works on the principle of inertia to measure the depth and force of earthquake. The sudden force of earthquake, makes the scale pointer to move and after the tremor, the pointer comes back to its initial position due to its inertia of rest.

Lighting is caused because of accumulation of electric charges between the clouds.

Seismometer devices are located in $$3$$ directions and work on the principle of inertia to catch the motions in all directions.

The nature of charge will be negative. When a negatively charged body come in context with uncharged metal paper clip then some amount of negative change will transfer from changed body to metal clip. This phenomenon of change transfer is called Conduction.

The large magnitude of the accumulated charges leads to the meeting of negative and positive charges producing bright light and sound i.e. lightning.

The vigorous movements of air current and water droplets causes separation of charges. Negative charges gets accumulated near the lower edges of the clouds.

The vigorous movements of air current and water droplets leads to separation of charges. The positive charges collect near the upper edges of the clouds and the negative charges accumulate near the lower edges.

Benjamin Franklin was the first to show that the lightning is electric discharge which is same as spark out of clothes during winter.

When the paper clip of electroscope is touched by hands, the foil strips collapse because the charges on foil strips gets discharged through our body.

When any of these materials are rubbed together, the one in higher order gets positive charge (+) and the one in the lower order gets negative charge (-). The correct frictional order is: glass, wool, ebonite and plastic.

By convention, glass acquires a higher charge than silk as it losses electron. So, on rubbing, glass acquires a positive charge and silk acquires a negative charge.

Plastic comes below fur in the frictional series of electric charges. So, fur will get positive charge and plastic rod will get the negative charge.

When two bodies are rubbed on one another, they acquire charges equal in amount and opposite in nature.

When a charged body is brought near the top conducting disc of an electroscope, the disc gets induced with charges. These charges run down to the metal strips hanging from the paper clip. Now as both the strips get similar charge, those repel each other and thus open up.

Electroscope is a device which is use to detect whether a body is carrying charge and also to detect the nature of charge on the body.

Steel is a good conductor. As soon as the steel spoon gets charged by rubbing with another object, the electric charge produced on its surface flow through our hand and body into the earth and the spoon remains uncharged.

Electroscope is a device that is used for detection and identification of charge on objects.

When the body gains electrons it gets negatively charged, because the number of negative charges are more than the positive charges, so the body becomes negatively charged.