User interface language: English | Español

Date May 2022 Marks available 2 Reference code 22M.1.SL.TZ1.11
Level Standard Level Paper Paper 1 Time zone Time zone 1
Command term Find Question number 11 Adapted from N/A

Question

The strength of earthquakes is measured on the Richter magnitude scale, with values typically between 0 and 8 where 8 is the most severe.

The Gutenberg–Richter equation gives the average number of earthquakes per year, N, which have a magnitude of at least M. For a particular region the equation is

log10N=a-M, for some a.

This region has an average of 100 earthquakes per year with a magnitude of at least 3.

The equation for this region can also be written as N=b10M.

The expected length of time, in years, between earthquakes with a magnitude of at least M is 1N.

Within this region the most severe earthquake recorded had a magnitude of 7.2.

Find the value of a.

[2]
a.

Find the value of b.

[2]
b.

Given 0<M<8, find the range for N.

[2]
c.

Find the expected length of time between this earthquake and the next earthquake of at least this magnitude. Give your answer to the nearest year.

[2]
d.

Markscheme

log10100=a-3        (M1)

a=5             A1

 

[2 marks]

a.

EITHER

N=105-M        (M1)

=10510M=10000010M


OR

100=b103        (M1)


THEN

b=100000  =105             A1

 

[2 marks]

b.

0.001<N<100000  10-3<N<105             A1A1


Note: Award A1 for correct endpoints and A1 for correct inequalities/interval notation.

 

[2 marks]

c.

N=105107.2  =0.0063095             (M1)

length of time =10.0063095=102.2

=158 years             A1

 

[2 marks]

d.

Examiners report

Many candidates did not attempt this question. Of those who did attempt the question, most of these candidates arrived at the correct answer to this part with the most common incorrect answer being 103.

 

a.

Those that were successful in part (a) answered this well.

b.

This was only answered correctly by the strongest candidates.

c.

This part of the question was a discriminator as correct responses were few and far between.

d.

Syllabus sections

Topic 2—Functions » SL 2.5—Modelling functions
Show 306 related questions
Topic 1—Number and algebra » SL 1.5—Intro to logs
Topic 2—Functions » SL 2.6—Modelling skills
Topic 1—Number and algebra
Topic 2—Functions

View options