Modelling vertical rupture plane with characeteristic fault source

[Jeongmin Han]

Hi,

 

I have a few questions with defining vertical rupture plane.

 

I modelled a simple pure strike-slip fault (dip=90, rake=0) by assuming that the fault rupture is across the entire plane using characteristic source model.

 

The hazard output appears with zeros for all sites and for all intensities. When I modelled the same fault using simple fault source and I got similar hazard results as I expected.

 

It looks to me that a characteristic source model cannot handle a pure strike-slip fault, instead it is applicable for rupture plance with 0 < dip < 90. Can you please comment on this?

 

Thank you in advance for your comments.

 

Kind regards,

 

Jeongmin Han

 

[Damiano Monelli]

Dear Jeongmin,

I do not think it's a problem of the dip angle. You can model vertical ruptures with both the 'SimpleFaultSource' and 'CharacteristicFaultSource' typologies.

With 'hazard output', do you mean hazard maps? If so, the problem could be the return period for which you computed the map (too small with respect

to the recurrence time of the event you are simulating in the fault). Try with a longer return period (i.e. lower probability of exceedance) or with a longer

'investigation_time'.

Best,

Damiano

--
You received this message because you are subscribed to the Google Groups "OpenQuake Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to openquake-use...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Jeong Min Han]

Damiano,

 

Thank you for your promt response and your advice. The problem with source modelling is now fixed.

 

However, I am still having a small issue with the hazard curve. When the hazard curve is generated, the hazard at lower probability of exceedance shows repeatitive values causing "flatten effect" in the hazard curve.

 

For example, exceedance prbabiltiies are equal for IML 0.55g and 0.6g as the table below. Can you please help me to explain for this case?

 

PGA (g)		Site 1
0.001		0.015915
0.01		0.015915
0.05		0.015915
0.1		0.015915
0.15		0.015915
0.2		0.015476
0.25		0.011519
0.3		0.008431
0.35		0.00489
0.4		0.003337
0.45		0.001781
0.5		0.000891
0.55		0.000223
0.6		0.000223

 

Thank you in advance for your comment.

 

Kind regards,

 

Jeongmin Han

[Marco Pagani]

Hi Jeongmin,

What's the level of truncation you're using? Can you set a larger truncation level?

Regards,

Marco

Sent from my iPhone

[Jeongmin Han]

Marco,

 

Thank you for your response. I did not truncated sigma.

 

That result was obtained from the Sadigh et al. (1997) GMPE with 0 sigma.

 

Regards,

 

Jeongmin Han

[Marco Pagani]

Jeongmin,

If you set sigma = 0 you're not taking into account ground motion
variability.

I suggest you to set sigma to something like 5 if you don't want to
truncate ground motion.

Best regards,

Marco

On 21/07/14 17:35, Jeongmin Han wrote:
> Marco,
>
> Thank you for your response. I did not truncated sigma.
>
> That result was obtained from the Sadigh et al. (1997) GMPE with 0 sigma.
>
> Regards,
>
> Jeongmin Han
>
>
>
> On Sunday, July 20, 2014 7:25:00 PM UTC+1, Marco Pagani wrote:
>
>> Hi Jeongmin,
>> What's the level of truncation you're using? Can you set a larger
>> truncation level?
>> Regards,
>> Marco
>>
>> Sent from my iPhone
>>

>> On 20/lug/2014, at 18:08, Jeong Min Han <jm.h...@gmail.com <javascript:>>

>> email to openquake-use...@googlegroups.com <javascript:>.

>> For more options, visit https://groups.google.com/d/optout.
>>
>>
>

--

*MARCO PAGANI* | Seismic hazard team coordinator | skype mm.pagani | g+
marco....@globalquakemodel.org | +39-0382-5169863

*GLOBAL EARTHQUAKE MODEL * working together to assess risk

*GEM -* globalquakemodel.org <http://www.globalquakemodel.org> | *T -*
@GEMwrld <http://twitter.com/GEMwrld> | *F -* GEMwrld
<http://www.facebook.com/GEMwrld>

[Jeong Min Han]

Marco,

 

Thank you for your suggestion and apologies for my confusion. I set the truncation level = 5 and it works fine.

 

Thanks for your suggestion.

 

Kind regards,

 

Jeongmin

marco....@globalquakemodel.org | +39-0382-5169863