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Science chapter 6
| Question | Answer |
|---|---|
| Seismometer | detectss earthquake waves |
| accelerometers | Measures changes in speed such as the shakes produced by earthquakes |
| earthquake | is a series of low frequency shock waves, somewhat like sound waves, traveling through the earth |
| what kind of physical quantity is a stress? What kind of stress. Is most likely to cause an earthquake? | A stress is a force exerted within a material. Shear stress |
| three types of tectonic forces | divergent boundaries- plates move apart Convergent boundaries- plates move towards each other Transform boundaries- plates slide past each other in opposite directions |
| (true/false) any change of shape Of an object due to stress is called a strain | true |
| (true/false) many geologists believe that it is gravity that ultimately drives sea - floor spreading | true |
| fault | occurs when the section of the rock on opposite sides of the crack move relative to eachother |
| what distinguishes a joint from a fault? | a joint is a CRACK in a rock along which there has been no MOVEMENT. A FAULT is a JOINT along which ROCK movement has occcured |
| How do. Geologists classify faults? | Geologists classify FAULTS by the way the TWO blocks of. Rock MOVED to form the FAULT |
| What kind of fault is the San Andreas fault | Strike - slip fault |
| geologists believe most earthquakes come from what kind of earth feature | faults |
| (true/false) pumping groundwater out of a rock formation containing an active fault could result in a more severe earthquake | true |
| what kind of instrument detects and transmits earth wave data to a central analysis station | SEISMOMETER; a seismograph also records the earth WAVES |
| list the types of earth waves an earthquake produces | P-primary S- secondary Surface waves |
| through which structure inside the earth can S waves not pass? What is the significance of this fact? | S WAVES cannot PASS through the earth’s core. Since this is true, geologists believe that at least PART of the core is LIQUID |
| Compare an earthquake’s focus and its epicenter | An EARTHQUAKE”S focus is the PHYSICAL location within the CRUST where the earthquake originates. It’s EPICENTER is the point on the earth’s surface directly above the FOCUS on the map LOCATION of the earthquake FOCUS |
| why are there lots of earthquakes around the Pacific Ocean | the PACIFIC PLATE is SUBDUCTING under other plates surrounding the pacific basin. These CONVERGENT TECTONIC boundaries are the locations for many active FAULTS that produce earthquakes |
| (True/false) because of the movement of seismic waves, scientists believe the core of the earth may be partly liquid | true |
| Tsunamis | devastating. They form when seismic waves shake a body of water |
| what is the highest magnitude on the richter scale | there is NO maximum value on the richter scale |
| what is the maximum value on the intensity scale and what would be the observed result? | the maximum value on the INTENSITY SCALE is XII. Essentially total DESTRUCTION within the EARTHQUAKE area would be observed |
| why is it difficult to predict earthquakes? | seismologists can’t DETERMINE with certainty the SIGNS that an EARTHQUAKE is about to HAPPEN |
| (true/false) an earthquake with an intensity of VI is 31.6 times more damaging than an intensity V earthquake | false |
| At minimum, how many seismic stations are needed to identify the. Epicenter of an earthquake? | At least THREE seismic stations are needed to LOCATE an earthquake’s epicenter |